Can He Unlock His Stepmommy's Ass?

My stepson is a man now, but he doesn't act like one. That's why my husband and I made a deal: my stepson can do anything he wants to any part of my body except my ass, that one is just for my husband. If he's grabbing my tits and making me suck his cock, maybe he'll learn a thing or two about being a grownup and stop acting up. Besides, cleaning his room might be easier if he's using me as a sex toy while he does it. To make sure he didn't cross any boundaries, my husband locked my ass, but I was so immersed in teaching my stepson how to tidy his things that I didn't notice he found the key! Sure, I felt the sex toy he shoved inside my ass, and I could have stopped him before he replaced it with his dick, but I was liking the way he was using me and wanted him to keep going. Maybe my husband doesn't need to know everything.