You've moved home with step-mom for the summer after graduating and she's excited to catch up. When you admit that your focus has been on getting qualified, getting a job and providing for her, not on dating girls, she's flattered but concerned. She doesn't want you to miss out on her behalf. Your attempts at changing the subject aren't working but then she starts acting off. Telling you it must've been the food she just ate, she excuses herself to the bathroom. But you're sure she's hiding something. That night you talk to her about what you saw and she eventually comes clean.
Step-mommy is a futanari. She has a huge cock as well as a pussy. She's been on experimental medication all her life but since you came home, for some reason the medication isn't working. She gets these urges and she's losing control of them. She admits that she's never told anyone before, but her condition means she's still a virgin. You were created through IVF and the story about your step-dad running away was a lie. She's been judged and self conscious all her life, so she's stayed away from dating, just like you.
Later, you get the news that you got the job you wanted, and it's so close you won't even have to move out. You can live with step-mom permanently! You're both ecstatic and you take her out to celebrate. And everything changes. You admit that you watched her masturbate the other night. She's embarrassed but feels the sexual tension too. Tonight was the best date she's ever had with a man. You lean in to kiss her and she doesn't resist. Are you sure you want this? She asks you to be gentle with her and you lay her down on the bed, sucking her beautiful tits until she asks to suck your cock. When she makes you cum hard in her mouth you offer to return the favour, then you lay her back down and fuck her. Though neither have been with anyone else before, it feels like you belong here, inside of step-mommy...
For fans of: taboo, impregnation, breeding, futa, pegging, stepmom roleplay