Mommy Gives the Best Birthday Gift to Her Step-SON

I've always known my step-son has had an obsession with me. I find my panties missing, I see his shadow through the door while I'm changing, he's constantly finds a step-son to come into the bathroom while I'm showering. Beyond that, I found his search history on our laptop. He watches a ton of step-mother/step-son porn. His birthday is coming up, and so I figure what better way to get him to stop fantasizing about me, than to give him the real thing. So for his gift, I allow him one day to do what he wants with me, and one day only. He takes full advantage of mommy's generosity, and it turns out, my step-son can make me cum multiple times.