I've been reading the stories on this site for a long time, and they never fail to get me going, so I thought I'd submit one of my own about the first time I actually came.
Like most guys, I started getting hard-ons around 10 or 11-years-old. At that point, I didn't realize what was going on and just accepted that those things happened. I didn't do anything about them until I was about 12.
That summer, I started to hang out at our local public library and found the books about puberty, adolescence, and sexuality. I would read about masturbation in these, then go home and try to attempt it that night in bed, but could never get it right. I would lightly stroke my cock with the tips of my fingers, making my hard-on just throb with ecstacy, but never actually make it to an orgasm.
Then, towards the end of the summer, I found a book at the library that showed a diagram of a hand wrapped around a penis. I remember thinking to myself 'So I've been doing it wrong all this time!' I couldn't wait until that night when I could try this new technique! After my shower, I went to my room, shut the door, and quickly got under the covers. Somehow, I knew this would be the night. I set myself up like I did every night with a bit of tissue in the hopes that I'd shoot something. I pulled my underwear off and just looked at my boner for a minute, like I knew it was going to be different that night. I then wrapped my hand around my cock like I had seen earlier in the book and started to pump up and down. (Even though I'm circumcised, the skin on my cock slides pretty easily over my head, so lube wasn't, and still isn't, necessary.)
The feeling was incredible, and while I'm pretty sure I didn't last more than a few minutes, it felt like an eternity. I realized that as I sped up my pumping, I felt like I was going to pee, but I knew from what I had read that this was normal and that I was almost there. I kept speeding up, and then finally, I came all over the tissue on my belly. It was fantastic! I knew at that point what I'd be doing every night from then on.