Only a couple that come to mind. My senior year of high school me and another guy on the team were very close friends, had been for a couple of years. One of the nights he came over to my place to stay the night. He found one of my porno mags under my mattress. And it was some bi sexual magazine so it had pics of guy, guy, girl and girl, girl, guy. I was in the shower getting ready for bed...was late probably about 1am or so. I came out of the shower and saw he had found my late night relief. I asked him if he liked what he was seeing and he was like yeah! And he was already pitching a major tent in his boxers. I went over to see what he was looking at and it was a pick of a dude sucking another dudes dick and the girl was sucking the other dude. I asked him what he liked about it and he responded that he had always been a little curious to be with another guy. So fast forward a few minutes- I had a kinky idea at the time. I asked if he wanted to put on some gear and wrestle for a few minutes so I could get boned up and I would help him with his curiosity. He stalled a bit and then said sure. So we fucked around play wrestling mostly but within a few minutes we both had major bones. I told him to go ahead and do what he wanted to do and I started pulling off his singlet and he did mine. We blew and fucked for a couple hours. As I recall we had two or three heavy cum shots. Funny thing is I always thought he liked dudes.
One other time I recall was at a meet. I was wrestling some dude- heavy, sweaty, rough match. He ended up getting me and won the match. Very sexy guy I was thinking too. Midway through the second period I was starting to get really aroused from all the testosterone, rubbing, being young shit like that. My singlet wasn't doing much to hide my stuff and I think my opponent started noticing too. Anyways...fast forward to the locker area where the guys went in and showered, changed. I trotted back there to shower and change and a few moments later my opponent came walking in- big macho walk and I noticed maybe he was walking that way because he had a major bone now too. He came over to me I told him nice match, you're a good wrestler... yada yada yada. He said yeah you're good too. And he came over and patted me on the ass and I noticed he gave a little squeeze so I did the same to him (I could sense some sexualness in the air I guess) and he looked me straight in the eyes and said I've got something better and more fun you can give a squeeze to. And he turned around and put my hand on his wood. I told him we couldn't do it right there so I took him to a secluded area out of sight upstairs to a classroom (the stairs from the fieldhouse went right up to the main levels of the school). We blew each other and he gave me a good 10min I'm horny/animalistic fuck and it was great- we were both so horny after wrestling.
I saw a lot of play shit stuff go on in high school especially... guys that congregated in the back of the lockers would sometimes have circle jerks to "blow off steam". And I saw some jerking off in the showers. The guys on the high school team I wrestled with were pretty uninhibited which was great. And I really think we had quite a few guys that weren't exactly straight.