Step-MOM and the Cursed Ring - The Time LOOP

I just found a little box and an old handwritten letter in my stepgrandma storage, while I was cleaning and throwing away the old and useless garbage. When I arrive home I read the letter and it says that under no circumstances to put the ring on because it's cursed. I don't actually believed, but when I try to put it on and in the same time my step-son arrives home and I drop the ring. I tell him the whole story and I try once again to put the ring on. I feel so strange, like there's magic in it. I start feeling the power of the ring and suddenly everything takes a whole new turn. My step-son keeps staring at me in a weird way, like he feels attracted by me. I hug him because I miss him then I see his erection I try to take the ring off and I get sent back in time. I realize what's happening although my step-son can't feel the loop. I must have done something wrong. What did I do wrong? When my stepgrandma mentioned the forbidden sin, that's what she meant, that when someone puts the ring on you feel lust for your own step-son. For the curse to be broken we must finish the act of sin, but finish it properly, I suppose she meant that my step-son has to cum, but when I tell hm the whole loop story, my step-son thinks he must ejaculate inside me. That can't be possible... How can I let my own step-son cum inside me? I start sucking his erected cock and I get really really horny for him and beg him to shove his cock inside me. He starts fucking me gently and drives me crazy, then fuck me harder and harder until he bows his huge load of cum deep inside me and I am dripping huge amount of sperm all over the carpet. After he ejaculates, we lay on the bed and wondering if the loop is still happening or we broke the curse.
It's a mystery for my next MOVIE!