I'm an 18 year old straight male and I have a friend, bisexual one, with whom I get along quite well.

As of late he has touched me on the crotch area, when we sit next to one another in class, despite me saying to him to stop and the other day at the swimming pool as we were putting ours bathing suits on he slaped me in the arse saying that I had a nice arse. Today in gym class, it happened again.

I have confronted him several times, asking if he wants to fuck me to which he always answer no, because I am not good looking, or not his type, but despite his answer he keeps doing that shit.

Is he hitting on me? Or am I overthinking this shit and he is just crazy?

P.S. I should also mention he only does that with me, but he doesn't have a lot of close friends, with whom he has the trust he has with me.