Super Sub

Category: DC Verse Television > SuperGirl
Dragon prints: 31081
Disclaimer: I do not own Supergirl or anything to do with DC. I do not make any money from the writing of this story.

Alex Danvers tried to be a good sister. It was literally the story of her life. She had looked after her younger sister when they were little, been her best friend and even joined the DEO to try and protect her. That was everything most people knew about her. Everything her Mom knew she did. Everything she was proud of. But there was something else, something she prayed no one would ever discover, that she had done in the name of being a good sister, and something she had tried so hard to stop doing. But when she came home to find a completely naked Kara Danvers, a.k.a. Supergirl, kneeling in the middle of their living room and looking up at her so hopefully it was hard to remain strong.

"Kara, we've talked about this." Alex sighed.

"I know." Kara said softly, lowering her gaze, "But I... I had a really bad day."

"I know." Alex softly parroted.

It had been all over the news how Supergirl had failed to save a family of four when some lunatic blew up a bridge, most of the news reports not even bothering to imply that it was Supergirl's fault. Instead they flat out said it, while mostly ignoring all the other families Kara had saved. Of course Alex, and everybody else, had tried to teach Kara that she couldn't save everybody, but Kara just wouldn't listen and always blamed herself for everything. Alex could see it in Kara's eyes, something she had sadly guessed would be there as she reluctantly made her way home from the DEO base of operations in Central city. She just hoped she could avoid Kara's usual coping mechanism.

"But you should be eating ice cream and watching your favourite movies." Alex pointed out.

"You know that doesn't really work for me." Kara said softly, "And it's not just... the bridge thing, Ms Grant was super tough on me, and Winn just won't take a hint, and everything just seemed to go wrong today, and I just... I just can't take it anymore. So please Alex, help me."

Alex sighed and step closer, "You should just ask Ms Grant to be your Dom."

Kara blushed furiously, "I told you, she's straight."

Smirking as she closed the distance between them Alex quipped, "And I've never fucked my own sister."

There was a brief pause, then Kara looked up at her and boldly told Alex, "You think what we have is ugly. It's not. It's beautiful. And good. And... and it's the only thing that gets me through days like this."

There was another pause and then against her better judgement Alex kneeled down, cupped Kara's cheek and softly said, "Nothing about you could ever be ugly."

Kara smiled, closed her eyes and leaned into the touch, while Alex desperately wished she could believe her own words. Well, Kara had always been beautiful, but the love they had for each other wasn't pure and innocent. It had been perverted by Alex's selfishness. After all, for all of her power and strength Alex had no doubt that Kara would have taken no for an answer that first-time. That she wouldn't have physically force the issue if Alex just had the strength to say no. But she had never been able to resist the sight of Kara on her knees, so instead Alex lent down even further and kissed her little sister for what had to be the millionth time.

Countless times Alex had promised herself this would never happen again, had told Kara it would never happen again, but it was a promise she just couldn't keep, and as their lips connected again Alex almost forgot why this was so wrong. Almost. But this wasn't one of those heated kisses were Alex forgot everything including her name, a.k.a. the type of kiss she was hoping to someday have with someone other than her sister. It was a slow, gentle kiss, the type of which Kara allowed her to have complete control, and the type which she knew enhanced Kara's feeling of submission.

Kara always had let Alex be in control because she was terrified of hurting her. Also it was therapeutic to submit to someone physically weaker than herself. And it felt natural. Everything with Alex had always felt natural to Kara, and she would never understand why humans had so many hangups about sex. To be fair she had been too young to know whether such things were so forbidden on Krypton, but she liked to think not. She liked to think it was a place they could have been happy together, at least when she allowed herself such bittersweet thoughts. But even on this planet there was an arguable grey area, given that Kara was Alex's adopted sister instead of a blood relation, although Kara didn't like to say it out loud as their sisterly bond was just as important to her as their sexual relationship.

Suddenly Alex broke the kiss, got up and smiled, "Don't go anywhere."

With that Alex walked into her bedroom, a.k.a. the one they shared pretty much on a nightly basis, even if a lot of the time they were just snuggling under the bed sheets and watching trashy TV, which Kara always enjoyed, just not as much as this. Like the well-trained sub she was Kara remained on her knees patiently for several long minutes, confident that her big sister would return to begin her favourite sisterly act. Sure enough after some rustling around Kara heard footsteps approach and found herself smiling up at her sibling, who smiled back before producing a little box from behind her back. Before Kara had time to wonder what was inside it Alex opened the box and the superhero cried out softly in pain and betrayal.

"Kryptonite?" Kara questioned, looking up at her sister with big blue eyes.

"Enough to neutralize your powers, but not do any permanent damage." Alex said sternly, taking the little black collar with the tiny green stone attached to it out of the box and then further explaining, "I took it from a pair of handcuffs which were able to restrain your cousin. If it's too much for you I can get something smaller, but I thought you'd appreciate the experience of truly losing control. And maybe I'm hoping it will finally put you off wanting to be my slutty little lesbian sub. Although I'm not holding my breath."

"Please don't." Kara said softly, before quickly clarifying, "Please don't hold your breath. Nothing could ever stop me from wanting to be yours."

"We'll see." Alex mumbled, before pushing, "Now, do you want to try the collar?"

"God yes." Kara replied without hesitation, "Please Alex... Mistress, give it to me. I want you to collar me. Please? I want to be collared."

Alex smiled softly and ordered, "Pull back your hair and stick out your neck."

"Yes Mistress." Kara quickly obeyed, unable to stop herself from letting out a small cry as her sister secured the kryptonite collar around her neck.

"Are you okay?" Alex asked softly, second-guessing this decision already.

"Yeah." Kara faked a laugh, before admitting, "It hurts, but it's nothing I can't handle. I swear to you, my Mistress, I'm okay. And I'll tell you if that changes."

"Good." Alex said softly, gently stroking her sister's hair, "But you should be able to take it off yourself, quickly and easily. It's just a clip-on. Here, why don't you practice taking it off and putting it back on as quickly as you can."

Kara nodded and then did as she was told, smiling in relief as Alex's words were proven true as she easily slipped off the collar. She didn't return to full strength right away as the evil green stone was still pretty close, but she felt a lot better and Kara knew that if she threw the collar just a few feet away she'd quickly return to her usual state. Which she almost pointed out to Alex who was watching her apprehensively, but as that would have been obvious Kara instead chose to just obey the second part of her Mistress's order and reattach the collar around her neck and then repeat the process. She wasn't able to use her super speed in that state, but it was still pretty fast, and she even shot Alex a cheeky smile a couple of times while dangling the collar away from her by the tips of her fingers.

"Good." Alex nodded to show her approval, "Now, put the collar back on and follow me in the usual way, Super Sub."

"Yes Mistress." Kara blushed.

Hearing that little nickname Alex had been using ever since she became Supergirl always made Kara blush and her submissive heart flutter, as it was a mockery of her superhero name, or arguably combination of it and her sexual preference. Either way Kara loved it, and the usual way she followed Alex in this state, namely crawling behind her on her hands and knees, following her big sister like the eager little puppy she was. Unsurprisingly Kara ended up following Alex into her bedroom, at which point she got back into the position she had been waiting for her older sibling in. Surprisingly she was then told off for it.

"Get back on your hands and knees!" Alex said sternly.

"Yes Mistress." Kara quickly apologised.

Alex then smiled, proud of Kara for her obedience, and her own ability/training for allowing her to tell what Kara was doing without turning around. It was cool and made her feel bad ass. Of course if Kara had her powers right now she could probably sneak something by her, but that was the point. Right now Kara didn't have her powers. She was completely and truly at Alex's mercy for the first time in their lives, and Alex was determined to make sure that Kara knew that. Which meant being in control even when her back was turned to her kid sister while she pulled out her draw of sex toys and pulled out a little paddle she usually used for a warm-up. Although hopefully today it would be more than that.

Turning around Alex showed the paddle to Kara, slowly approached her and then announced, "Let's see just how effective that collar is, shall we?"

Before Kara could reply Alex quickly raised the paddle up and brought it crashing down on her baby sister's butt. Kara had looked disappointed when Alex had revealed the paddle 'which didn't do anything', but when Alex connected with her target Kara let out a loud cry of pain and betrayal and then straightened herself up and started rubbing her butt. The cry she let out made Alex second-guess this whole thing, but the adorable look of surprise on her face quickly made it worth it. Then that look of surprise turned to delight, and despite herself Alex couldn't help but get turned on by it.

"Oh my God, I actually felt that!" Kara exclaimed, slipping out of character.

"I'm glad." Alex said dryly, unsure if she was lying or not.

"No, you don't understand." Kara insisted, "I REALLY felt that. Before I was mostly faking, even with your 'good' toys, but that... wow. That felt so good."

"Are you sure?" Alex pushed.

"God yes!" Kara exclaimed desperately, quickly slipping back into her submissive mode, "Oh God Alex, that felt so good. Please Alex... Mistress, please spank me again with that toy. Spank me with all of your toys! Beat my butt! Beat it bright red! Please Mistress Alex, I've been waiting my whole life to get a proper spanking, and now you can finally give me one. You have too! You just have to beat my butt!"

There was a long pause and then Alex softly asked, "Kara, who's the Mistress?"

Kara frowned in confusion, "I-"

"Who. Is. The. Mistress?" Alex asked in a dangerous voice, "Is it you?"

"No Mistress Alex." Kara shook her head, "You're the Mistress and I'm just your bitch."

"Then why are you topping from the bottom?" Alex asked softly, then when Kara couldn't meet her eye kneeled down, cupped the usually stronger girls chin and easily pulled it upwards so her younger sibling was looking her directly in her eyes, "I should beat your ass for that, but because that's what you want I'll just use my hand."

"Yes Mistress. I'm sorry Mistress." Kara softly apologised.

Alex smiled, "But it will be over my knee, just because I know you like that."

Kara beamed, "Thank you Mistress."

Then, because she couldn't resist, Alex kissed her sister, lingering there for longer than she should have before pulling away and slowly putting the paddle away, sitting down on the bed and softly ordering, "Well, do you want to get spanked or not?"

"Yes Mistress. I'm sorry Mistress." Kara softly apologised, scurrying to get in position.

There was then a pause, partly to build anticipation for them both, but mostly just so Alex could admire Kara's cute little butt being presented to her. Cheekily Kara wiggled that ass ever so slightly, obviously trying to entice Alex to spank her while trying not to make it obvious that was what she was doing. Unfortunately for her little sister Alex could easily see through the trick, and punished her for it by making her wait even longer for what she wanted. It also gave Alex an opportunity to put a hand down and play with Kara's ass for a little while, squeezing and pinching the cheeks like a butcher examining a piece of meat, which of course made Kara whimper in frustration.

"Mistress, please..." Kara whined, "I need it. I need to be spanked."

That wasn't true. Kara wanted to be spanked, not needed too, and Alex considered pointing that out and/or making the little brat wait even longer to get what she wanted. But truth be told she was just as eager to spank her sister as her sister was eager to be spanked, so instead Alex raised her hand and brought it down as hard as she could on Kara's cute little ass. For once Alex was 100% sure that the cry that Kara then let out was real, which made her smirk in triumph. She had always hated the way Kara played along, because it made Alex felt like a failure as a Dom, and as twisted as it was she wanted to give her baby sister what she wanted, even if that was a hard spanking.

Kara was so happy she felt like she could cry. The pain of that first hard strike just felt so wonderful. Exactly what she needed. And it was a need, despite what she knew Alex thought. She just couldn't help it. She needed this kind of pain and humiliation. It was what she wanted. What she needed. What she craved. Part of it was survivors guilt, after being one of the only ones to survive the destruction of her home planet, but mostly she was guilty for failing all the people she couldn't save. That as incredible as they were her powers could fail her when she needed them the most, or she might make a mistake, and that was the difference between life and death. And maybe part of her was also guilty of having those abilities when others didn't. Especially those like Alex who could maybe make better use of them.

Growing up Kara had always secretly wished that Alex was exactly like her. She was still an awesome companion, but they could never have a race or spa or really do anything physical truly together. Worst of all Alex couldn't hurt her when she needed it. But now she could, which made Kara so overwhelmingly happy, a feeling which didn't subside when the next half a dozen spanks were nearly as hard as before. Honestly Kara had been expecting it. After all, ever since they had started their affair Alex's main way to dominate her was to deny her what she wanted, just giving her a little taste to keep her on the edge before finally delivering it. So at first it didn't even annoy Kara. At first.

Of course Kara had never been a patient person and it wasn't long before she was whimpering, "Please Alex, spank me harder! Harder! I can feel it, I swear. Oh God, what you're doing feels really good, but I want more. Ohhhhhh yeah, I want you to beat my butt. Please? Owww fuck, that's it, just like that. More. No! Don't stop! Alex?"

The more she tried the more Alex seem to tease her, either randomly giving her one hard strike and then going back to the mild spanking which preceded it, or worse making the spanks even more gentle. Kara tried everything she could think of, or at least everything that wouldn't hurt Alex, like call her sister by her real name instead of her proper title of Mistress Alex, being as whiny/bratty as possible and even threatening tell their Mom, the last one especially working well in the past but not now. Finally she just gave up and whimpered and literally cried at the frustration of being so close to what she wanted and not having it.

Ironically shortly after that Alex actually began giving her what she wanted, slowly increasing the power behind her strikes until each one echoed throughout the room, and more importantly caused the most wonderful sensation of pain which caused Kara to cry out joyfully. Just when Kara didn't think it could get any better Alex began slowly shortening the time in between each spank until her loving big sister was beating her butt as fast and as hard as humanly possible. Which with her currently dulled senses really did feel like one directly after another, for once Kara glad that Alex was human because of a kryptonian or something like that did this to her even she wouldn't have enjoyed it. Instead things were perfect, just perfect, and Kara was literally crying with joy.

Alex couldn't know that for sure, but she strongly suspected it given the way that Kara wasn't stopping her. Because sure, she din't currently possess her super strength or speed, but she could tell Alex to stop at any time and she would. Or she could use their safe word. If she could remember it. Or she could take that collar off and end her pain, one way or another. But she wouldn't. Kara had asked for this, beg for it, and now Alex was finally giving into her she couldn't imagine that her baby sister would ask her to stop. Especially considering how her soaking wet little pussy was currently ruining Alex's pants, which was both extremely hot and annoying.

Using that annoyance and every other single thing that had frustrated her about growing up with Kara as a foster sister Alex hit the kryptonian's ass harder than any other body part on any other alien or human, which was way more satisfying for them both and should be. And not just because Kara wasn't the only one getting wet, although that was pretty disturbing. Alex was actually finding it therapeutic to exercise her Demons in this way. It wasn't like before when this just left them both mostly frustrated, only able to find satisfaction in being humiliated and humiliating the other, this was real pain being received and dished out, and it felt really, really good.

Thanks to the relentless assault on it Kara's firm little ass jiggled ever so slightly with the force of every blow. Even better than that its slowly turned light pink, dark pink and then eventually an angry red and bruised red under the battering of Alex's hand. It was so wrong, but Alex honestly didn't think she'd ever seen anything more beautiful before in her life. And even when the super powerful alien's butt became red and bruised Kara didn't complain or retaliate. No, she continued to take it, and seemingly love it just as much as Alex did, perhaps proving that much to Alex's dismay that the two sisters were indeed perfect for each other.

Of course Alex wasn't a super powerful alien. She was just human, and she had her limits. She pushed those limits like never before, spanking her little sister long beyond the point that her hand and arm started to ache and tire. Hell, she briefly considered switching to the other hand just so she could continue the brutal butt beating. But no. She had other plans for her super sub. Plans which would either finally convince Kara to stop coming to her for her twisted needs, or would cement their twisted relationship once and for all. Alex should be rooting for the former, but in this moment of weakness as she effortlessly flipped her sister around in her arms and then kissed her, she couldn't help but hope for the latter.

Kara was definitely hoping that it would cement their relationship, something she tried to make very clear when Alex broke the kiss, "Oh my God Alex, that was amazing."

Not wanting to believe it Alex gently wiped Kara's face while softly pointing out, "You're crying."

"Happy tears." Kara insisted, gently taking the hand that was wiping her face, and had just beaten her butt, and softly kissed it, "I promise."

Alex looked thoughtful for a moment, and then ordered, "Get on your knees."

"Yes Mistress." Kara quickly obeyed.

Kara wasn't sure where she should kneel, as unfortunately this was one of the times Alex didn't specify, but taking a risk she dropped to her knees and then shuffled back a few feet. Mostly because she was hoping that Alex was about to get naked. Luckily that was the case, and while Kara was horny and would have liked Alex to be quick about it the truth was she preferred when her big sister slowly stripped in front of her as it gave her more opportunity to anticipate what was about to happen, and admire her sexy body. Plus Alex only really looked hesitant once at the beginning, the rest of the time she seemed to be deliberately teasing Kara, which filled Kara with even more happiness and excitement.

She was even more giddy when Alex finally removed her panties, revealing Kara's favourite thing to lick. And she had no doubt she would be soon licking it, but how soon? Would asking for it make her wait longer for it? Maybe make her beg for it? Kiss her feet? Both? Oh she loved the idea of both, or either one, but not as much as just getting right to it, given that she had been thinking about little else all day. Again as luck would have it Kara got what she wanted, Alex first beckoning her forward and then roughly grabbing her hair and shoving her face first into her cunt. Kara didn't even have to let her, making sure she didn't have the strength to resist. Not that she wanted too. Hell, Alex barely got the chance to order her to do it before she started.

"Lick me Kara, lick my pussy oooooooooh Goooooooodddddddd!" Alex moaned loudly, taking a long moment to get her bearings before continuing the verbal encouragement, "That's it, lick me just like that, ohhhhhhhhhhh yesssssssss, mmmmmmmm, don't tease me Kara. Just make me cum. Mmmmmmm yeahhhhhhh, I want my baby sister to make me cum! Ah fuck!"

Strictly speaking Alex should have probably punished Kara for being so eager at the beginning without permission, or even saying 'yes Mistress, thank you Mistress' like a good sub should. But Kara was glad she didn't, because for the most successful spanking session ever clearly both sisters were ready for Kara to perform her duties as Alex's personal pussy licker. And not with slow, teasing strokes of her tongue either. No, Kara went right to the rapid and needy licks, at least partly because she had to do if she wanted to get even the majority of Alex's juices. Because Rao, Kara had never seen Alex so wet before, which was really saying something considering she was very good at turning her sister on.

After a very short while it was tempting just to shove her tongue as deep into Alex's pussy as it would go and then tongue fuck her big sister to orgasm. Given Alex's current condition it would be so easy, but no. Kara was a good sub, a super sub, and there was a limit to how disobedient she was willing to be. So she would been strong and wait for permission. Not top from the bottom, again. Because once was bad enough, but twice in one session? No, Kara would wait for permission to make Alex cum. Which was why she made sure to mostly avoid her sister's clit, prolonging the pleasure for them both, no matter how desperately Kara wanted to taste the heaven that was Alex's cum.

Alex could tell how badly Kara wanted to make her cum, how badly she wanted to taste her cum, and that pure desire for her helped push Alex closer to the edge of orgasm. In a way it was nice to be wanted from just about anybody, but to have her little sister lust over her had always been truly intoxicating for Alex, even though it shouldn't be. It was so wrong, and Alex knew she should be disgusted, but she just wasn't, at least not at that moment. No, in that moment she was struggling not to shove Kara's face as deep as it would go into her cunt and order her kid sister to make her cum in her pretty little mouth and all over that superhero face.

It was almost overwhelming, but at least for now Alex held back. Partly because she wanted to maintain her dominance over Kara, and partly because she wanted to prolong her own pleasure, but mostly because of her own stubborn pride. After all, she had held back from cumming despite Kara's best efforts before, so why would she give in so soon? Well, it was tempting, but Alex would rather maintain her air of dominance than receive quick satisfaction. Besides, it was what Kara wanted. Perhaps even needed. Yes, Alex didn't like to encourage such thoughts in Kara, but maybe her little sister really needs a dominant Mistress which could help keep her in her place.

Such thoughts definitely didn't help Alex with her growing desire for an orgasm, so she did her best to block out such thoughts in favour of going over the cases she was currently working on, and even some old ones just to take her mind off it. As a result her mind briefly drifted to her missing father, and what he would think if he managed to return only to find that she had perverted her relationship with her sister and violated the perfect creature she had promised him she would protect at all costs. Which was always too good at dampening her desire, guilt overwhelming Alex for a few long seconds before she concentrated on the breath-taking sight of her kid sister in between her legs, which quickly wiped those thoughts away.

Concentrating even briefly on Kara's pretty little head in between her thighs almost made Alex cum, so as soon as she thought it was safe she closed her eyes and tried to block out what her adopted sibling was doing to her. Like everything else this was just a temporary fix, and arguably the worst because even with all of Alex's training to resist torture she couldn't block out the torturously wonderful pleasure she was receiving. Hell, it even made everything she was experiencing that much more intense, a liberty Alex permitted for herself for a little while, before it all became too much and she was forced to open her eyes and start trying to concentrate on the mundane things in her room.

Of course while Alex may be one of the most resilient humans on the face of this earth, or any other, she was still exactly that. Human. She had her limits, and it was only a matter of time before she couldn't resist the literal goddess who was currently on her knees for her. Which was something Kara reminded her every time her eager tongue touched Alex's clit. Because even though Kara was being the perfect sub and only touching Alex's clit as often and with as much force as she was allowed it was still enough to drive Alex crazy. Everything Kara did always drove her crazy one way or another, and all she could do was direct her to go slowly as possible.

"Okay, now you can suck it." Alex whimpered, "Ooooooohhhhhhhhh yeahhhhhhhhhhh, suck my clit, oh Karaaaaaaa aaaaaaaaahhhhhhhhhh!"

Temporarly losing the ability to speak Alex was almost literally forced to her knees. More accurately she was forced to her butt, her legs no longer having the strength to hold her up properly, forcing Alex to sit down on the bed to support her weight while she tried to regain the ability to tell Kara to make her cum. Because she just couldn't take it anymore, she needed to cum, and worst of all she knew Kara wouldn't do it without permission, not because she was deliberately trying to tease her, but because being a good sub was that important to her. Just like being a good Dom for her sister was that important to Alex, which was why the older sibling found the strength to say what she needed too.

"Kara..." Alex said weakly, "Make me cum. Tongue fuck me. Ooooooooh yessssssss, fuck me, OOOOOOOOOOHHHHHHHHHH GOOOOOOOOOODDDDDDDDD, OHHHHHHHHHHHH KARA!"

Pretty much as soon as Alex gave permission Kara pushed her tongue inside her. Which was hardly a surprise. Kara was eager to obey, and at the time Kara had been taking a break from sucking  Alex's clit to licking the entrance to her cunt, sneakily decreasing the pleasure and heightening her sister's desire for a tongue inside her. Normally Alex wouldn't have taken the bait, but she just needed to cum so bad. In fact she was surprised that she didn't cum as soon as that tongue entered her, and she probably would have if the penetration had been just a little bit harder. On the bright side Alex got to enjoy the feeling of Kara's tongue slowly sliding inside her and then beginning to thrust in and out, her kid sister officially starting to tongue fuck her.

It was that thought just as much as the tongue fucking which sent Alex over the edge of an incredibly powerful orgasm, the older sister tightening her grip in the younger sister's hair and pushing her face deeper into her cunt as she threw her head back and let out a loud guttural cry. She then continued to cry out, and scream, and even whimper as she came wonderfully hard into her little sister's mouth and all over her face. And the worst part was Alex wasn't thinking about how Kara was her foster sister and there was no real blood between them. No, she couldn't stop thinking about how for as long as she could remember this girl had felt like her sister. And she was making her cum. And the fact that her sister was making her cum wasn't distracting or subtracting from the experience. No, it was exactly the opposite. It was only making her cum harder for her baby sister.

Kara loved making Alex cum. It was pretty much her favourite thing in the whole wide world, but especially when her face was pressed right up against Alex's pussy like it was right now, meaning that she would either get hit right in the face with her big sister's cum or she could really swallow it. During that first orgasm she chose to greedily swallow every single drop, Kara using her super speed to remove her tongue and seal her lips around it so that heavenly liquid could flow straight into her mouth, down her throat and into her belly were it belonged. Then when there was no more cum to swallow she pushed her tongue back inside Alex and repeated the process, so for the second climax Kara let her big sister cum all over her face.

Honestly Kara wasn't sure which one she loved more. When Alex squirted onto her face it felt like she was being marked as property of Alex Danvers, Kara feeling like hours or even days later people were looking at her and somehow seeing a drop of girl cum on her face and recognising her as a rug munching slut who loved pussy so much she couldn't stop gobbling her own sister's muffin. But maybe some would be jealous too. Either way they would all know she was Alex's. Sadly that wasn't really true, as boys continued hitting on her, but it was easier when she felt like she could still feel Alex's cum on her face, even if she had made sure to clean it off.

Except for the cleaning it off part that's how she felt about walking around with Alex's cum in her belly, and the taste of it in her mouth. Except, in her mind, it wouldn't be as obvious that she was her sister's sub, and while that would be bad in real life the fantasy was incredibly powerful. Of course while Alex came in her mouth she got to taste it, and nothing, not even Alex's pussy cream, could compare to the pure heaven in liquid form which was her big sister's cum. Oh Kara could never get enough of tasting her sister's cum, which always made this choice so hard for her, and she loved them both, and she knew Alex loved them both too.

Ultimately she tried her best to do both, although it wasn't easy. And Alex wasn't exactly helping by backing grinding her cunt into Kara's face. Sure, was another thing which made her so wonderfully submissive, and normally Kara loved it, but with the kryptonite collar securely around her neck she wasn't fast as usual and she even felt a little faint as Alex began fucking her face. It was almost enough to make Kara remove the collar, but she didn't, because here was everything she'd ever wanted. To be helpless and completely under Alex's control, the person she trusted over everyone else using her as a fuck toy. If that meant the majority of the cum ended up on her face instead of an even amount on it and in her belly then so be it.

Alex always got a little lost in her own pleasure at this stage. It had never been a big deal before as Kara could easily take any amount of abuse she gave her, leaving Alex to enjoy multiple orgasms. But this time was different, and somehow Alex had forgotten that somewhere between Kara sticking her tongue inside her and making her cum. Which wasn't actually that surprising, but it certainly didn't excuse her actions, Alex feeling overwhelmingly guilty when she finally realised what she was doing and immediately pulled her sister away from her cunt and kneeled down to see if Kara was okay. Maybe she should have known better, but she was kind of delirious from the pleasure she'd just received.

Certainly Alex was being a little stupid for trying to ask if Kara was okay considering how much she liked to be abused, and more importantly how much she liked to eat pussy. Because of course Alex would barely get a chance to open her mouth before Kara would practically attack Alex with her mouth. At least this time her powers were dulled so it didn't hurt when Kara shoved her tongue into her mouth, Alex found it easier to encourage the other girl to slow things down so they could savour the kiss, and Alex could savour tasting herself in Kara's mouth, and on her little sister's lips and tongue. Then after a few minutes of that Alex pulled back, receiving a goofy grin from her sibling.

Taking a calming breath, and audible gulp, Alex asked, "Do you truly want to be mine?"

"More than anything." Kara promised.

"Then prove it." Alex challenged, "Give me all your holes."

Kara smiled shyly, "I already have silly."

"Have you?" Alex raised an eyebrow, then when Kara looked at her in confusion pushed, "Really think about it, have you?"

Kara thought about it then frowned and confessed, "I don't get it."

"Your butt. I want to fuck your butt." Alex explained, and then when she wasn't sure if Kara looked embarrassed or confused added, "I want to fuck your butt hole with my strap-on."

"Oh." Kara blushed.

"Of course we don't have too, but-" Alex began.

"Do it." Kara interrupted, her eyes lighting up, "Oh my God Alex, that sounds so painful and humiliating. Please do it. Fuck my butt! Please Mistress, I want you to fuck my butt hole. Use it like you use my pussy. Make it your fuck hole. Please? Fuck my ass and make it yours."

Alex let out a soft gulp and commanded "Get on the bed on your hands and knees."

It would always amaze Alex how Kara could be so hesitant to swear in public, and most of the time they were alone together, but then she got turned on and it was like a switch had been flipped and she was suddenly Alex's Super Sub again. It was amazing, and so hot Alex struggled to maintain control of her senses, just as it was a struggle to tear her eyes away from the sight of Supergirl on all fours and waiting for her, but she did in the name of performing the ultimate forbidden act, and perhaps trying one last effort to push Kara away. Although it looked extremely unlikely at this point. Either way Alex retrieved her harness, strapped it to her and lubed up the dildo in the daze before taking her place behind Kara on the bed.

Then after a moment's hesitation Alex cautiously pushed a finger into her little sister's virgin ass hole, causing Kara to softly cry out, "Oh Rao!"

"Are you okay?" Alex asked nervously.

"Yes." Kara blushed, "Please keep going, mmmmmm, oh Mistress, it feels so good."

From her tone of voice Alex doubted that Kara was enjoying this in the traditional sense, at least entirely, but if she was experiencing discomfort or even pain Kara would probably enjoy that even more. So Kara began thrusting her finger in and out at the same slow and cautious pace she had neutral in the first entering Kara's previously untouched back hole, the entire time amazed at the incredible tightness she felt. Although considering who this was Alex should consider herself lucky her finger wasn't being crushed. Not that the thought stopped her from pushing her luck, first by pushing a second finger up her sister's butt, and then replacing it with her dildo.

"Just relax, okay?" Alex softly murmured as she did it.

"Okay." Kara whispered, doing her best to obey.

Kara then gasped as her poor little butt hole slowly began to stretch, her eyes widening along with it until the head of Alex's cock finally slipped past her anal ring and into her virgin ass, making the mighty Supergirl cry out pathetically. It hurt so bad during those first few seconds, but it was mostly out of shock. She'd received far worse, at least physically, but the damage to her pride was like nothing she could ever have imagined. And it... it was actually kind of nice. Kara loved submitting to Alex so much, and this was a greater submission than Kara could have ever thought of. Or could have thought she could possibly take. And most amazingly of all she wanted more.

After a few long seconds Kara even croaked, "More. Give me more."

Without needing to look back Kara could tell this took Alex by surprise, and her protective big sister had been on the verge of asking if she was all right and/or if she wanted her to stop, despite the fact that Kara had taken far worst pain in her life, and would no doubt do again. Although it had certainly been unique pain, one to a lesser extent Kara experienced again as Alex slowly and cautiously pushed forwards, causing inch after inch of long thick dildo to slowly slide into her widely stretched back door and deep into her back passage. But as well as pain there was also something else, something which deeply embarrassed Kara. Which of course only made her like it even more.

She continued to feel like that as the anal penetration was slowly completed, at one point Kara thinking it would never end, the dildo suddenly feeling longer and thicker than it ever had in her pussy or mouth, and the next Alex's thighs were resting against her butt cheeks, announcing that her big sister had buried every single inch of that strap-on cock deep within her butt. Kara had what felt like an eternity to try and get used to that weird feeling, although it was probably only a couple of minutes until Alex slowly started to thrust her hips back and forth, causing the dildo in turn to slide in and out of her ass hole officially beginning to give Kara her first ever butt fucking.

As Alex began pumping her butt the initial pain and weirdness briefly increased, and then faded away disturbingly quickly, leaving Kara feeling only amazing pleasure. And a tremendous amount of embarrassment. Kara had thought she had known just how twisted she was. What kind of forbidden things she needed to get off. But this, she could have never imagined enjoying this. But she did. Not with anyone else. Just with Alex. With her wonderful old sister who knew her better than she knew herself. Maybe even more than she was aware of, because both sisters seem to be amazed when shortly after the sodomy began Kara began moaning softly in pleasure.

Alex hadn't truly believed this would put Kara off their forbidden affair. If she had been she probably wouldn't have done it. But she definitely wasn't expecting her to moan in pleasure from it. At least not so soon after violating her most private hole. The fact that she did only proved that Kara was even more of a submissive slut than Alex thought was even possible, which was really saying something considering the depths of depravity she had engaged in with her adopted sister. Of course while this revelation should disgust her it only turned her on more, just like everything else they did together which they shouldn't.

It also pushed Alex to reward Kara with a few harder thrusts, which got a few extra loud moans from her baby sister. However while those moans were mostly of pleasure Alex swore she could hear a tinge of pain within them. Not much, but enough to make her quickly slow down. Besides, she was having too much fun to rush this. Because God, Alex was actually doing it. She was sodomising her little sister, and they clearly both loved it. Fuck, they were both so screwed. It had been a long shot, but this had been Alex's last chance of saving them from this ultra-forbidden affair, and now Alex truly didn't think it would ever stop.

As she watched her cock slowly pumping in and out of Kara's incredibly tight butt hole Alex couldn't even pretend to be disappointed by the idea that there would be no end to this. That the Danvers sisters would continue fucking each other in secret, regardless of any potential consequences. That Kara would forever be her submissive little slut. Hers to use and abuse however she wanted. That National City's resident superhero would be her personal pussy licking whore. That Supergirl would be her anal slave. Oh yes, Alex really loved the sound of that, especially as she pulled Kara's ass cheeks apart to get a better view of her strap-on dick violating most private hole on her sister's body.

Shortly after that Kara whimpered, "Harder! Mmmmmm, please Alex, fuck me harder!"

The incredible sight of Supergirl's ass hole stretching for her strap-on was so captivating that Alex didn't even register the words, nor did she a few seconds later when they were repeated. It was only when Kara whined them a little louder did Alex realise what was happening, and it startled her so much that she almost gave in right away. But no. She was the Dom here, not Kara. Something she need to make clear, because while Kara could be the perfect sub when it came to receiving pain she was a total brat when it came to her own pleasure. And again, Alex was having too much fun to rush the first of many times that she butt fucked her kid sister.

Kara had tried to hold out and let Alex decide when to give her ass a real fucking, but she just couldn't help it, it just felt so good. And yet not good enough. Because wow, it felt like she was on the edge of cumming already, and all she needed was a little push to finally give her what she wanted, and maybe what she needed. Which was mind blowing, and eye-opening, considering how she hadn't thought she was like this at all. After all, pain and humiliation was totally her thing, but she had thought butt sex was just a step too far. But she couldn't have been more wrong, because it felt like her butt was made for fucking, and the fact that she hadn't tried this yet would now be one of her biggest regrets in life.

It helped a lot that while she was apparently a natural butt slut Alex was a natural butt fucker. Because of course she was. Alex was awesome, and always gave her what she needed, not what she wanted. She was so lucky to have Alex as a big sister, and more importantly a Mistress. Kara just prayed to Rao that Alex was getting even a fraction of the enjoyment she was getting right now as her constant begging fell on deaf ears and her big sister continued gently sodomising her. Of course as much as Kara loved the unique mix of pleasure, submission and humiliation she was receiving it was only a matter of time before her begging became increasingly desperate.

"Please Alex, fuck me hard!" Kara whined loudly, "I need to be fucked! I need to be fucked in the butt. Please Mistress, fuck my ass. Mmmmmmm fuck, fuck my ass hole hard and deep and make me cum. Ooooooooh yeahhhhhhhhh, I need to be fucked hard and cum with your dick up my butt. Please Mistress Alex, pleaseeeeeeee ohhhhhhhhh, fuck me! Fuck me hard! Ooooooooohhhhhhhhhh, make me yours Alex! Make every last part of me yours! Make my ass yours. Ooooooooooh yesssssssss, fuck my ass hole and make it your fuck hole! Ohhhhhhhh Goooooooodddddddd, you can fuck it whenever you want, I swear, just make me cum. Oh God, oh Rao, oh Mistress please, please, OOOOOOOOOOHHHHHHHHHH GOOOOOOOOODDDDDDD, AAAAAAAAAAHHHHHHHHHHH FUCKKKKKKKKKKKK!"

Thankfully it was also only a matter of time that Alex took pity on her, moving her hands from Kara's ass cheeks to her hips so she could finally give her what she had been begging for. Not right away, loving Mistress that she was Alex slowly built up to it, which in a way felt like forever and yet at the same time it only felt like seconds until Alex's thighs were smacking off her butt cheeks, making Kara feel like she was getting spanked again as the dildo hammered her most private hole. The sound of flesh smacking off flesh was wonderfully loud, almost as loud as her screams of pleasure as her body shook and Supergirl received her first ever anally induced orgasm.

Just like every other time Alex fucked her Kara received multiple climaxes, but they had never been quite this frequent before or so hard. It almost hurt, especially that first-time her cum squirted from her cunt. Which would have been extremely embarrassing for Kara, if there was any part of her conscious mind left. But there wasn't. Because it felt like her mind had been literally melted inside her head, which was worrying as given everything she had seen it wasn't impossible for that to actually happen. But Kara couldn't really worry about anything right now, which unfortunately included her big sister's safety.

Alex was taken aback by just how hard Kara came. She knew her little sister had been enjoying it, that she was a natural anal slut, but she had no idea how much until that moment, and it became even clearer when Kara lifted herself up onto all fours and started slamming herself backwards against the anal invading thrusts. Which had only happened one time before, and Alex had been immediately knocked off the bed and broken her arm in the process. It was an embarrassment which both sisters remembered very well, and even though Alex punished her for it she was confident even if she hadn't Kara wouldn't do it again. And she hadn't, until now.

To Alex's relief the kryptonite collar continued to do better than she could have hoped for, meaning that while the pure shock almost knocked Alex off again the older sibling was able to hold firm and continue sodomising the younger one. It didn't even hurt really, in fact Alex really loved the passion Kara showed for such an obscene act, and while she got the feeling Kara was trying to use her super speed mostly without success she did seem to be going slightly faster than the average human. Certainly Alex struggled to keep up with her, although she liked to think she did pretty well considering, and together the Danvers sisters made sure that Kara came frequently and wonderfully hard.

Of course she wasn’t the only one, the stimulator inside of the harness constantly bashing against her clit and the sheer joy of ass fucking her goddess of a sister ensuring that Alex came over and over again too, although obviously not quite as hard as Kara. Which probably helped push her through those climaxes, along with the fact that she had a lot of practice at fucking her sister with a strap-on, but ultimately Alex had to stop. Of course, that didn't mean their fun had to be over. No, because as always when using her favourite toy Alex gave one hard thrust to bury it inside of Kara and then roll them over so she was on her back with the blonde on top of her, giving Kara a chance to finish the job.

The difference was that this was twice as long as normal thanks to Kara immediately removing the kryptonite collar with shaky hands, throwing it away and then starting to hammer herself up and down with every ounce of her Kryptonian speed and strength until she was a blur. Somehow she managed to avoid breaking Alex's pelvis in the process, although the bed wasn't so lucky, and with a creaking came tumbling down around them although both sisters were too busy cumming to notice. It actually became painful, Alex letting out a pitiful whimper which was probably the main reason seconds later Kara gently collapsed on top of her, although Alex didn't see how even Supergirl couldn't be exhausted at this point.

"Oh Rao, that was amazing!" Kara grinned as she fell, and then looked up hopefully at her sibling, "Please do that again?"

Against her better judgement Alex smiled softly, stroked Kara's cheek and whispered softly, "Anything for my Super Sub."

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