Turnabout is fair play

Jill looked at her brother her soaking bald pussy was currently rubbing against his spent cock while the remnants of his last orgasm dribbled down her chest. Her recent makeover was perfect for her current body in the way she shimmied her hips made Mark feel utterly justified in his actions to make her sexier. Jill grinned playfully swivelling around so that her fine ass hotdogged his shrinking shaft leaving the cum drunk boy feeling a little bit out of it.

Before Mark could really do anything in his dazed state, Jill was already typing on a keyboard, A few quick commands that belayed her skill at typing far beyond his.

The first changes were immediate but also incredibly erotic. Mark felt his stamina suddenly going from depleted to almost full again his semen soaked serpent was already starting to return to full erection while his body started to firm up. Mark wasn't a fat guy but he definitely wasn't in the best shape that was about to change as he felt faint but definite muscles gently forming in all the right places. Not a gym bro, but enough to give the ladies something to look at what their bouncing on his cock. He felt his balls gently swell expanding until they roughly doubled in size while his thick 12 inch balance trembled with new unbalanced energy. He didn't have any tattoos but he did feel his hair grow a little bit thicker as his body bulked up just enough to enjoy his sister's voluptuous form rubbing against his.

Mark grasped his sister's hips groaning as he felt his cock finding its place inside her and moaning as the pair made out again he could taste himself on her lips a strange salty sensation that somehow didn't really bother him as much as it ought to.

In fact it excited him knowing that his sister was impaled in his lap. He let out a moan savouring the sensation of losing his virginity, He'd made his sister into a perfect tattooed perverted slut and it was only natural the turnabout was fair play they were partners in crime as well as partners in bed and while both of them would probably bed innumerable men and woman in the near future there was something very special about your first time.

In fact with every thrust it felt like she was getting tighter,

A quick look down revealed why. Jill's belly was now swollen obscenely the outline of a massive member far bigger than the one he'd put into her was clearly outlining every inch of her distended womb. Mark gripped his sister's hips groaning as he delighted in the sensation of stretching her out so much another impossible gift by the perverted program.

"Finally noticed my little gift," growled Jill gently stroking the bulge in her belly causing both of them to tense up with perverse delight.

"You made it so big I figured I might as well go whole hog don't worry it will only get this big if the girl can take it," she added making sure to roll her hips and elicit a massive moan from both of them.

Mark didn't hesitate in fact he took the opportunity to take one of his sister's pierced nipples between his lips gently nibbling and sucking on it as she continued to push herself to fulfilment.

His tongue roamed along her pierced barbell the cold metal providing the perfect complement to the warm salty flesh and the fact that the breast in question was larger than his head only made the pleasurable whining of his sister even better. And throughout the whole experience he started to notice that they were getting bigger everything was getting bigger

With each raise of her hips Jill seemed to somehow be getting deeper, getting heavier and throughout the whole process Mark's member kept growing bigger and thicker.

5 feet, 6 feet 7,8 eventually the crest of Jill's head rubbed against the ceiling lightly knocking her each time he thrust into her with a womb destroying battering ram

The celestial a gifted stud thrust upwards feeling the chair wheel starting to buckle from the increased weight until eventually with a sudden crack the chair fell over.

And yet somehow the pair didn't stop if anything Jill seemed to get a second wind thrusting on slamming herself down continuing to grow larger and larger her Titanic ass slapping against his balls. Generously juices gushed all around them and Jill began mumbling the filthiest and most erotic things that Mark had ever heard.

It wasn't just her, Jill wanted to have her perverted way with everyone, the world was their oyster and between the two of them it would become a sexual paradise.

Mark kept thrusting occasionally amending a fantasy marvelling at the gorgeous pervert currently crushing his cock, he didn't hurt he was physically fit enough to keep going even under these circumstances

The rutting siblings didn't stop, building through crescendo and crescendo Jill's juices sprayed both like the torrent of a geyser before long Mark finally felt his cock twitching in response he looked up into the elated enormous face of his giant sister fingers digging into her enormous ass as he pushed his massive member as deep as it would go groaning and gasping with delight as he felt thousands of sperm spurting towards their inevitable target. The siblings had a need to breed and more than the correct equipment to do so with a massive heaving sigh brother and sister exploded together. Max almost felt like he was being drained physically but his new physique helped him survive his impossibly huge member swelling out his sister's stomach like a bowling ball.

Mark reluctantly pulled out leaving a pool of steaming semen leaking from his gigantic younger sister. At 2 feet long and as thick as a Coke bottle it was hard to imagine anything more robotic even as his mammoth member shrink down to its original size in a matter of moments. He stayed down at his sister marvelling at her rounded belly and feeling a surge of arousal. If he hadn't managed to breed her now it was only a matter of time before that particular bridge was thoroughly crossed. His sister had probably never imagined this kind of thing before but it was now forever etched between them. Mark was going to breed her and probably every friend or relative he got a chance with

Still stumbling a little bit Mark finally took stock of his transformed body. Although he was definitely a lot better built he was still recognisably himself evidently his perverted sister had wanted to keep him at least somewhat looking like her elder brother. A bit more muscle a little bit more hair and a lot more energy. He gently stroked his cock suddenly aware that his perverted sexual desires were a lot more fluid than before probably just what Jill had done in response. He preferred girls, but now the idea of sucking a cock or having sex with another man were not off the table, providing they were girly enough

Mark looked at the commands finally able to process something other than his sister's pussy. He suspected that his sister had done quite a lot pretty quickly and probably opened Pandora's box as a result

Mark looked down at his body, He was still himself, just a lot better defined and with a lot more purpose in his life. The perfect stud to go along with his slutty little sister. There were a lot of things he wanted to try now, his sister had made sure to open his mind but also give him a new focus similar to her obsession with incest his obsession would be with making sure that every attractive person that crossed his path wound up fostering the next generation.

He looked at his broken computer chair wondering what the next step should be.