When I was 9 or 10, an older boy at school had managed to make me stay after the school session was over, there was no one around. He took me to the boys room and had me stand next to him in front of the urinal, so I though he was going to pee, instead he took his cock out, which was already hard, and started to masturbate, but I did not really understood what he was doing. He had me drop my ;pants and briefs and told me to do like him. Strangely enough I became hard but yet still did not understand what was going on. Then he started cuming but kept on masturbating to the point where his cum turned white and foamy, and I was wondering where all this stuff was coming from, I was perplex. We had several more such meetings after school was over and then he started to masturbate me to show me how to do it. One weekend, maybe the next year, we went to a public swimming pool and after swimming he took me to his changing cabin, had me sit next to him, and masturbated me until I started to have goose bumps all over my body and felt this strange yet wonderful feeling. He looked at me and said "My god, he is actually cuming." We started to go to that pool on weekends and did the same thing over and over again, then I moved on and lost my interest playing with this boy who was probably gay now that I think about it.
A few years later, when I was about 13 I was masturbating frequently, at the very least once daily but usually more. My best friend, a neighbor and schoolmate would often come over or I would go over to his place whenever his parents, or mine, were not home, and we'd play, masturbating each other, then we started to put fingers in each other's anus, then a year or so later started to experiment with anal sex, taking turns. This whole thing came to an abrupt end when one day my mother came home from work unexpectedly early. We were both nude and masturbating together and had not heard her coming in (we had quite a large apartment in Manhattan). She opened the door and caught us in the act. She sent my friend home, told me to stay nude, came back to my room with a large wooden hairbrush and proceeded to spank my bare bottom until I was crying like a baby and pleading for her to stop. She also called my friend's mother and informed her of what had transpired, and she in turn administered a severe spanking on my friend's bare buttocks (this was in the (this was in the early 1960s were teenagers were still commonly spanked in many household).
Having learned a very valuable lesson, we both refrained from masturbating together at our homes and instead grabbed opportunities, mostly on weekends, such as going to the YMCA to use the pool. We masturbated together until about age 16, then came the girls ... I keep in touch with my friend who, like me, is straight and married, but I must say that I fondly remember those days.