This all happened when I was 13...
The first time I ever did 'stuff' with another guy was one day after school. I went back to his house for dinner and we were upstairs in his room. We got talking about sex and stuff and I asked him how much he had done with a girl. It turned out neither of us had done anything.
Anyway, talking about this got me horny, so I asked if he had ever done anything with another guy. He said he hadn't. So I asked him if he'd ever thought about it. He said he had and I told him that I had as well. By this time I knew I was on a winner because I could see the bulge between his legs.
I asked him if he wanted us to wank in front of each other. He seemed nervous so I said I would go first. By this time my cock was rock solid, and I was only too happy to get it out and stroke it. I undid my jeans and got it out and started to rub it slowly. He didn't wait much longer and soon enough we were both rubbing our dicks. It was a real turn on to do it in front of someone. We had similar sized dicks. Both about five inches long, mine was maybe a bit thicker, but nothing significant. Looking at his dick really got me horny and I could feel an orgasm getting closer and closer. I stopped rubbing my dick and asked if I could do him. He said yes so I went over and grabbed it and gave him a vigorous handjob. He was actually moaning with pleasure, I was quite proud of myself!
After a while he grabbed mine too and started to jack me off. We kept going for about five minutes. He came first shooting his cum all over my leg. But that wasn't going to stop us! He carried on and soon after I came all over his carpet.
We carried on doing stuff together until we were about 16 and lost touch. It was quite a regular thing, even when we were with girls!