How can I get some closure on an experience I regret?

Back in high school, my friend and I used to masturbate around each other. I hate even talking about it now because it's so weird. We didn't even realize how messed up it was at the time. One time, it escalated and we ended up doing it for each other. It wasn't supposed to be a gay thing, but it sure sounds like it now that I talk about it. I pushed this away until it recently came up in my head again. I'm having a lot of trouble.