I am 48 now but was 11 at the time and in my first year at senior school. We had been playing football and were in the pavilion changing rooms. Most of the lads had left and there were just me and two others left, Mike and David. All of a sudden I heard Mike ask David to jack off in front of him. He said he would but not in front of me. I wanted to say that I didn't mind and would love to watch it also, but I just said it was ok as I was going now anyway.
The thought of what they would be doing after I left made me feel as randy as hell. I went up into the main school building, into a toilet cubicle and had to jack off as well. It was one of the best orgasms I ever had, although I didn't shoot hardly any cum at that age. I still wonder, even now, what it would have been like to stay and watch. Even though I am not gay, it is still my fantasy to jack off with another man.