When I was 15...
The summer after my freshman year I was horny as ever. I had only made out with a girl and nothing more. My friend, Chris, and I would always talk about sex and girls but never actually think about doing anything together.
One day, Chris and I were changing after taking a swim in the pool. We had changed in front of each other before but I had never seen anything but his ass and he has probably only seen mine as well. This time, I noticed him looking over at me while I was naked. He quickly looked away once he noticed me. I asked him what was wrong and he said, 'Nothing.' I laughed it off and finished getting dressed and so did he. He immediatley started talking about sex and I knew he was horny. The conversation eventually led to masterbation. We discussed how often, how long...etc. I was very hard and I assume he was too. During a very akward silence after talking, I asked if he wanted to jack off with me (just as friends). He said yes and sounded almost relieved. We sat on the bed and pulled down our pants and boxers. We were both about 7 inches, cut, and very hard.
He started pretty slowly and made my strokes look much faster. I scooted closer to him until the sides of our bodies were touching. I looked at him for approval and then slowly moved my hand across his stomach, through his pubes, and worked my way up his shaft. I remember it felt exactly like mine. He went straight for my dick and started massaging the head and working his way down. From jerking myself, I had a small amount of precum on my dick and he rubbed it and then spread it down my shaft. That is still one of the most amazing feelings I've ever had. He started getting really into stroking my dick and he suddenly got up and sat on top of me. He then pressed his dick to mine and stroked them together.
By now, the heads of our penises were bright red and wet from the precum of both our dicks. He kept stroking faster and faster until I knew I couldn't hold back much longer. Luckily he started moaning loudly so I knew he was probably close to his climax. He started cumming just a few seconds before me but we finished at more or less the same time. As his first few drops of cum shot out of his dick, they landed on the head of mine and I came harder than I had in my life. The rest of his cum and mine got on his hands and my stomach. We were both pretty tired and he plopped down on top of me. After cleaning up, we decided we should do this all the time and we did for a few years. He gave me some of the best orgasms I've had to this day.