Your bitchy step-sis comes in being her usual self to you, steals your cup (a secret concoction you've made to ruin her life) She cares so much about her looks and how other people view her, it will ruin her life to have a dick. She falls into a deep nap as planned, and wakes up to her horror to find a dick replaced where her pussy usually is. She panics and screams, trying to yank it off then turns to blaming you. But then the uncontrollable urge to stroke and cum takes over her, she starts humping and moving her hips, she can't hold it off, she demands you turn her back but its too late she starts stroking her cock desperate to cum, it feels so good, and she even encourages you to get yours out, she cums all over herself, but it doesnt stop, the urge has gotten stronger, she is now distressed but cant stop wanking, she demands you change her back as she wanks herself off again and rubs it all over her tits. she is covered in her futa cum and threatens to fuck you with her futa cock if you dont change her back, but you continue to watch her as she switches between being submissive and horny to distressed and angry, she cums all over her tits and mouth, tasting her own futa cum but her pleasure quickly changes to panic as she realizes she is stuck in a wanking loop - with every cum she gets hornier and more unable to control but she can't stop the urge to cum . She is violently wanking as she threatens to fuck you if you dont change her back. The problem is you dont know how too...