Changing room at day camp
When I was 12, I went to a day camp with a big swimming pool. We did not have big locker room, instead we had changing rooms we shared with one or two other boys. I shared mine with this boy who sort of weird. He would wait till I was changing to go to the pool, then come in and watch me strip. In retrospect I am sure he was gay. Thing is, I have since experimented with being bi, and liked it. I sometimes masturbate imagining he and I are doing each other's dicks.