Turns her into cocksleeve for science

You begin almost manically as you set up on your sister. You don't even bother with any more formalities grabbing her by her arms lifting her up high and slamming her on your massive member. Your body is singing with hormones as you feel your DNA start to rewrite gaps evening in is your body literally uses your excess mass to reconstruct into a new form. You weren't exactly a skinny guy

So naturally once the hormones are done flowing you gain quite a bit of mass in more appropriate feminine places, your belly has shrank but your excess fat hasn't been left dormant. You feel your massive breasts pushing against your sisters head as you grabbed her by the ankles and slammed home. Every thrust makes your cock even thicker and your rubberised sister even more of a **** to it.

Your husky voice is an aphrodisiac charm and a luscious lips find hers just as quickly as you slam into her making out as you become the pinnacle of both male perfect fusion with the best characteristics of both. You are the impossible made possible and with every brief second a new torrent of ecstasy is unleashed.

Marky! " Screams Alice as you release yet another stream of juices from between her legs punching her womb with your fantastic phallus. And finally it's time you feel your entire body twist and clench as a fantastic and amazing double orgasm completely shatters your mind and you complete your purpose spraying what feels like a fire hose deep into a sexy mad scientist