You picked out a Halloween costume for your step-mother, doing a bit of a trick or treat thing, and a nasty trick in that you got your thick and curvy step-mother a very tight skimpy outfit! You're going to a family costume party for her work and you picked out the costumes. You're the only step-son and she's a single step-mom and you're a bit closer than most moms and sons, you get naked in front of each other despite your age, etc. You've always had the hots for her but she lacks confidence and doesn't dress very sexy, always covering up her big butt and fat titties. So you're ecstatic, trying to cover your boner in your Robin costume as she strips off her satin robe and starts putting on her pushup bra, garter and black leotard. She catches you staring at her cleavage as she bends over to clip on the knee socks. She puts on the wig and the witch hat and looks amazing, your boner is aching but you feel so confused and guilty. She notices your boner and is nice about it, then gets on the bed to lace on her high heeled booties you picked out. Once she's dressed, something changes...your step-mom is different...dirty...assertive. She tells you that you can't go to the partner in such a tight outfit with a boner like this so it must be taken care of. She tells you to take it out and jerk it for her, and makes you clean the rental heels with your mouth, taunting you in such a forbidden way! She's sexual with you, and very dominant, and you can't do anything but exactly what she says, which includes worshipping her ass, sucking her heels, being called humiliating names, and more.