My first interest in sex probably began when I was 7 or 8. At church we didn't have bathrooms in the building, so we had to go to a bathroom facility that was in the school yard in back of the church. Often I would meet up with a fellow (probably in his 20s or 30s) sitting outside the bathroom moving his hand up and down on his penis slowly, then rather rapidly. This interested me, but I had no idea what he was doing. In fact, I did not even know the word "penis." I came from a single-mother family with no siblings, and my mother was never into discussing sex.
I have had several interesting times since I started masturbating. When I was about 9 years old, I worked on a neighbor's farm. They had a son in his 30s, unmarried, whom I worked with a lot. He would feel me up and put my hand on his penis, and eventually I started to masturbate him. To me his penis was so big, but to a 9-year-old, I guess it was. Then one day when I was about 10, I walked into the barn and caught my cousin going at it. He was 5 years older than me. He was to the point that he couldn't stop, so I saw him ejaculate.
I am 15 and very excited there is such a site as JackinWorld. The first time I ever masturbated (of course that's not what I knew it as), I was 7 or 8 years old. It happened when one of my friends who was the same age came over and showed me how he touched himself and said that it felt good -- so I had to do it, too. Although we never touched each other, it was still fun. From then on I used the regular "Fist" hand grip with spit as a lube. I did this until I was 9, and then I started to masturbate in the shower using soap or shampoo, which I know now is not good for you.
I am 29 and have been masturbating since I was about 7. I can remember as a child being very interested in my penis and the things it did.