The summer I had turned 11 my cousin came to visit and was staying with us for about two months. Because our house was small, he would sleep in our camper in the backyard. My parents asked me to sleep there too so he would have some company. My cousin was 13 at the time. The first night he was there we talked about girlfriends and I learned he had done things like spin the bottle, played with his girlfriend's breast, but not much else. Some time in the night we talked about our dicks and with a flashlight I showed him mine and he showed me his. He was a lot bigger than I was because he was in the middle of puberty and I wasn't. I was amazed he was getting some hair on his nuts and above the base of his cock. Other than size, out dicks looked the same.
A couple of days later, we were just hanging out in the trailer with my best friend, who was 12 at the time. He and I had been playing with each other's cocks since I was about age five because he was like my brother and we shared everything with each other. Neither he or I knew anything about sex, but just did things to each other that felt good. My friend and I often wrestled nude together when our parents were gone and I suggested we show my cousin how we like to wrestle.
My friend and I stripped and had a couple of wrestling matches on the bed in front of my cousin. Both of us had boners and it was fun with my cousin watching. Next my cousin wrestled me nude and it was exciting being pinned by a bigger guy and feeling his big boner slide against my skin. Next I watched him wrestle my best friend nude and seeing them grab each others boners while locked together in a wrestling hold gave me a funny feeling in my gut.
After my friend went home, my cousin asked me if I ever jacked off. I told him I didn't even know what that meant. He described masturbating and told me he would show me how. We stripped again and lay next to each other on the bed. He explained to me about cum and having an orgasm, but I was still confused because I had never heard about these things. My cousin showed me where to grip his boner and how to stroke him, adjusting my pace to his liking. He did the same to me.
After a while, he started moving his pelvis in a way that indicated to me he was really feeling something. I stopped stroking him but he asked me to keep going. I now sat up and started stoking his cock some more until he again started moaning and thrashing around on the bed. This time he urgently asked me to stop but I just gripped his cock tighter and stroked him faster. I was real curious about seeing this to the end. My cousin's body started jerking and suddenly a stream of fluid shot out of his cock onto my hand.
Surprised, I let go of him and he jumped off the bed. He pulled on his pants and ran out of the camper. I was surprised by his reaction and wondered if I did something wrong. In a little while he came back laughing and explained to me that he had just had his first orgasm, but for a moment had gotten scared thinking he was going to piss all over the bed.
That night he asked me to jack him off again, only this time he knew what to expect and I got a chance to really examine his orgasm as I gripped his cock in my hand. I experimented with him, by jacking him off every night for the rest of his stay and learned a lot about bringing him to the edge. A year and a half later I reacted the same way to my first orgasm, as my best friend was jacking me off and it was great!