Super Sub

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."