Your step-dad hasn't had "the talk" with you, has he? I know boys at your age get certain urges and feelings "down there". I've caught you jerking in our master bedroom one too many times now and I'm tired of finding your cum all over my nightgowns! I haven't told your step-dad because I didn't want to embarrass you, but I've had enough. You are going to stroke for me right here, right now since you're such a little perv. If you don't, I'm going to show your step-dad all the dried cum in our bed! I'll also tell him that I caught you peeping on me while I was showering, he won't like that. So you will jerk off for me and cum on my command. Step-mommy always knows best.