All true to the best of my memory, but a long, long time ago.
Mel and I were buddies, both thirteen years old, and lived across the street from each other. He was ahead of me reaching puberty.
One day when I had the house to myself Mel came over and asked me if I would like to try something new. A few minutes later we were both lying on the living room floor with our pants down around our knees, and Mel told me to start rubbing my penis while he did the same. I did as he said but, to be honest, I don't remember anything special happening. When I asked Mel what was supposed to happen, he told me about an 'incredible feeling' and suggested I try another time. I guess he had an orgasm then, but I sure didn't.
I took Mel's advice and kept on trying, usually while alone in the bathroom, and one day experienced the most intense feeling I'd ever had. I found myself holding my breath, tensing all my muscles as I felt as if something was being pulled out of my body... I was having my first orgasm and it was amazing. After that time I tried to duplicate that feeling as often as I could, and still enjoy masturbating to this day.