I first found out about masturbation when I was about 11. I was lying the bathtub, and I noticed that my penis was hard and erect. So, I thought I would touch it, and I ended up pumping it up and down. It felt good, and I was soon shocked when I had my first orgasm. I started doing it many times per day, and have continued for several years. I found on the internet that masturbation was completely normal, and found out even more ways to do it, thanks to this site and others.
Anyway, here is my story. I was staying at my Grandmother's house over Christmas last year with my cousin, who was 12 at the time. We were passing some time on Christmas Eve in the basement, throwing a ball around (I know, it sounds stupid). Well, the game got more and more ferocious, and we were throwing the ball as hard a possible. Well, and errant throw from my cousin hit directly in my genital area. I let out a yelp, and grabbed my scrotum through my pants. I sat down, and the pain started to subside. She asked me what happened, and I told her how the scrotum was very sensitive. She then apoligized, and asked if she could do anything to help. I said no. The pain had went away, and I was starting to feel somewhat horny (I never thought of my cousin in a sexual way until now). So I got the idea that I would show her my genitals. I said 'You don't mind if I expose myself, maybe it will make it hurt less'. She said 'of course not, do you want me to leave', and I said 'no, you can watch if you want, just promise not to tell anyone'. She agreed, and I pulled out my 'parts'. She gasped, and said that she had never seen a boy's penis before. I started rubbing my scrotum, and she asked if she could help. I said sure, and she started rubbing my balls and rolling them around. I was certainly aroused by now, and my penis was starting to get quite erect. She asked what was going on, and I told her in a very 'medical' way what happened during sex. She said that she had heard a lot about it from her friends. She then asked if she could touch my penis, and started stroking it up and down. She did this for quite some time, and when I was about to come I asked her to stop. I put the 'parts' away and thought that that was that. She then asked if I wanted to see her 'privates'. I said certainly, and she took off her shirt and bra, exposing her budding breasts with large, puffy nipples. She also took off her pants to expose her near-perfect pussy with just a few hairs starting to sprout. I touched her breasts, and rubbed her pussy a little, and she moaned then I did that. I then, without notice, started sucking on her nipples. She moaned loudly (I told her to keep it down), and continued. She told me how good it felt and how she had never felt like that before. I said, 'do you want me to continue'?, and she said absolutely. I then started licking her pussy, and did so for quite some time. She had three orgasms while I was doing it. After we finished, she said she had never felt so good, and I then explained how she could do it herself with her hands. After we sat for a while, she said she was starting to get 'those feelings' again and if I didn't want to put my penis in her and have sex. I said that it could be dangerous, and she said that she didn't care (not to mention that I didn't shoot cum yet). She then stripped off, and said to go ahead. I licked her some more, and then after she was wet, slowly slipped my penis in. I had never felt anything like it before. The feelings were so incredible. Then I started pumping. Her body was twitching, and I was getting ready to come. I said 'are you ready' and she said yes, so I continued to pump faster. She started shaking, and I felt her vagina contracting on my penis, and then I had the most incredible orgasm ever.
After we were through, we laughed about it. We have never donw it again, but we have talked about it a few times.