:The Succubus Fantasies:

You approach your sister. You like the size the of her. She's rounded and bulging and curvy. She's fat and also incredibly sexy. She's chewing on the blue pill, just like your were chewing on the pink. Your little button of a cock is standing to attention, but you push towards her and it's clearly not going to work. You don't have the length to fit inside her. You can feel your bellies up against each other, but there's no way you'll be entering her.

Then between your legs your feel something, but it's not you, it's her. The blue pill is changing your sisters body too. You step back and see, above her vagina, where there used to be a clitoris is now a large dangling horse cock. Your sister smiles. "I want my body back now!" she tells you. She grabs one of your tits and begins to suck.