This entry was found on the Male Sexuality Survey at http://male101.com/faqs/pn/first-orgasm.html. It was submitted by an anonymous heterosexual male.
My first (orgasm) happened shortly before my twelfth birthday. I was really naive and had no idea what masturbation was, but from the time I was a young boy I found a great thrill in pulling down my pajama bottoms in bed. I often fantasized about getting caught with my pants down and that my dad would use the opportunity to spank me as I bent over the edge of the bed. As I pretended I was being spanked, I would thrust my hips against the mattress with each imagined swat. After a few of these, I had an involuntary contraction of my sphyncter muscle and I thought I was going to dump a load right there so I stopped. I thought that was weird so I thrust a few more times and it happened again. I wasn't experiencing anything pleasurable but I decided to see if I could make it happen again. I continued thrusting my penis against the bed, but nothing would happen. Determined to get that sensation again, I kept going until I felt compelled to go faster. After a couple of minutes I felt something building up in my penis and I thought it was getting ready to happen again until there was a sudden rush of extremely intense pleasure in my penis followed by a really self-conscious feeling and an overwheming need to pull up my pj's immediately! I wondered what that was. I thought I had discovered something nobody else could do. Twenty minutes later I was doing it again and it felt every bit as good. Incidentally, to this day, I've never had that same contraction that started the whole thing. It was several weeks before I realized that a tiny bit of clear fluid came out each time.
The first time I had a proper ejaculation was nearly a year later. It was a snow day and I was bored at home. Watching an episode of the old superman series, I challenged myself to see if I could masturbate to an orgasm during the commercial. When the commercial was over, I had to stop and wait for the next commercial. My first couple of attempts were unfruitful. By the third time I was really ready to go for it. I used my preferred method of rubbing against the bedspread. Up to this point I left little wet spots which would evaporate pretty quickly without leaving a stain. I would cover them with a pillow or book and an hour or so later they would be gone with no stain left behind. I really went for it on this commercial and sure enough, I had an extremely long satisfying orgasm. To my surprise as I stood up to pull up my pants, I found a large long puddle of milky white fluid on the bed. I thought I had broken something. I covered it with a dirty towel and thought nothing of it. Over the next few days I repeated the same process until I started notice that where I had left these little puddles, there were elongated spots where the bright red color had began to fade on the bedspread. I also looked at my top sheet where I was leaving similar puddles after bedtime and found that the bright blue had faded in several similar locations. This new stuff left evidence behind and there was no way to hide it. I always hoped nobody noticed, but now it's obvious to me that my parents and especially my older brother who I shared a room with never said a word about it. I actually wish now that my brother had said something so I wouldn't have continued to feel so self-conscious about it. I had that bedspread for another two years with those obvious stains on it. That's when I started to develop my hand technique, and always took a handkerchief to bed with me to clean myself up.