Aggression

Sup y'all recently my boyfriend and i have begun taking our relationship much more seriously. We both slept together about three weeks ago and it was his first time but not mine. Since then we now have frequent sexual contact. However I feel as though I am much more dominant and have more of a say of when and where we have sex. I find that I get really aggressive and start beating him and squeezing his penis incredibly hard. He says he enjoys it but I can tell he doesn't and that he's just saying it to keep me happy. It is having a serious toll on our relationship and I really don't want to lose him. Please help, it's like another person takes over and I don't know how to stop.