My first orgasm came completely by accident. I was playing with a vibrating massager. It was the type that you strap to your hand to help you massage someone or yourself. My dad had circulation problems, and used this on his leg on occasion.
I was sitting in my fathers favorite chair in the living room where he kept the vibrator plugged in, and had been playing with it quite innocently. Being ten it was kind of difficult to keep it on my hand for very long, and since I hand been play with it for a while, I had to take it off. It was, of course, designed for an adult hand.
Without switching it off, I slipped it over the end of my hand, and dropped it into my lap.
Well, THAT turned out to be an eye-opener! I couldn't believe what was going on! In the blink of an eye, I had a hardon and my first (dry) orgasm.
To make things more interesting, my father walked by and noticed what was going on. He gave me an odd look, but kept on walking.
Well from then on, the massager was constantly missing from the table next to my father's favorite chair. (I 'borrowed' it quite often.) I figured out that I could wrap my penis in a washcloth and slip it into the straps where your hand would usually go. After switching it on, it wouldn't take long before the orgasm came. (wow!) Pulling my penis from the center of the cloth would, at the same time, clean up and feel great. Most of my favorite masturbation orgasms came while using that massager.
Eventually, my dad had to get another massager. He never really found out what happened to the original, but probably had a pretty good idea...