Learning masturbation from some friends.
When I was 12, I hung around three neighborhood friends who were aged 13 to 15. One day we were over at David's and they talked about watching David masturbate. I had never seen anything like that, nor had I heard of it. I'd heard the term 'jacking off', but knew nothing about it.
David's mother was home, so we locked ourselves in his room, and while Carl, Robert and I sat against the wall, David got on his bed, pulled his shorts down and propped up a Playboy in front of him.
His cock looked huge to me, and it all seemed strange at the time, since it was so new. David worked himself for several minutes, and then I saw him tighten up, and start stroking faster. He grunted and some white stuff shot out of his prick. I was amazed. After that, the other guys started doing themselves. I joined in, and we watched each other as we stroked ourselves.
Robert and Carl came, and I had my first orgasm, which felt amazingly good, but I had no semen coming out.
We had several sessions over the summer. We never touched each other, but it was funny how we quietly cheered when one of us had our orgasm.