My boy's friend Blackmail Becomes LUST

When my step-Sons friend comes over for dinner and accidentally overhears a big family secret, he uses it to his advantage to blackmail me for sex. The last thing I want is this self-centred college boy telling everybody in town that I'm fucking my own step-Son! I agree because I love my step-Son (maybe a little too much) and meet him at night for a quick fuck in exchange for him keeping his mouth shut. I strip for him and then lie back whilst he pushes himself inside of me.. and it isn't long before I'm practically BEGGING him to fuck me harder.. deeper.. faster.. GOD his cock feels so good! I pretend that I am tipsy and didn't mean any of my sexual display.. I then tell him to leave, but he's back again a few days later, showing up at my house uninvited, letting himself in whilst my step-Son is still at college. I tell him No, but he just.. does something to me.. makes me feel.. hypersexual. He bends me over in the bathroom, rough fucks me and finishes in my mouth. I spit his cum in the sink. The next day he's back again, this time asking for a sleepover with my step-Son. I agree and when my step-Son leaves the room we arrange to meet in my bedroom in the early hours. Later that night he comes into my room where I am waiting for him totally naked on the bed. His dick is so hard for me as he squeezes himself into my pussy.. fucking me in missionary and then I climb on top of him to milk his cock from above.. and thats when.. my step-Son walks in and catches us.