A friend at school told me about 'jacking off' on the bus on the way home one day. When I asked him what that was, he was really matter of fact about it. He said something like, "you just take some Vaseline and start rubbing." He didn't bother to tell me what would happen after that.
I must have been pretty young when I started because as I started and I got hard, it felt so good that I kept going when I started to cum. The only thing was...I wasn't greeted with my first load of cum--I started peeing like a racehorse! It freaked me out while at the same time experiencing my first orgasm.
Later on as I started to perfect my new hobby, I shot my first load and that kinda freaked me out too, but I knew what was 'cumming' I just didn't know when.
I still continue to perfect my technique.