When I was a freshman in high school, I met a guy who would become my best friend and I would usually go over to his house after school and hang out. His parents worked, so we usually had the house to ourselves, until his younger sister came home.
We were a couple of horny teenagers and were obsessed with sex. One day, he showed me some pictures he had cut out of some sex magazines that he had found somewhere and asked me if it was okay if he jacked off with me in the room. I think we had been swimming and he wanted to get out of his wet trunks when he asked this. We had gym class together and had already seen each other naked, so I said sure, and he whipped it out and started stroking.
He encouraged me to do the same and gave me some pictures to look at. He was on his bed and I was on the floor and we eventually looked at each other. I noticed he had a very strange technique, which was to use all five fingers to grab his penis from the end and pull on it, kind of how you'd hold an egg. I used the standard closed fist when I did it.
His parents had a stash of porn tapes locked in a metal box in the garage, but he was able to pry it open with a fork and we started watching these tapes. His family also had a satellite dish and even though his dad had locked out the Spice and Playboy channels, he knew the unlock code and we'd end up masturbating together watching the television.
We never touched each other; we just jerked off and enjoyed ourselves. He had always teased me about his sister, saying that she wanted me to be her first and all that stuff, and I always acted like I didn't like her. She was two years younger than I (8th grader), but in reality, I was really attracted to her and to this day I feel like an ass for not doing anything about it because I am sure she liked me, too.
After two years, for some reason my friend thought I wasn't cool enough to hang out with anymore. I guess he wanted to be a jock and started hanging out with a different crowd, but I fondly recall sharing those moments mastubating together, as that was the first sexual experience I had with another person.
I also want to add that when I was in either the second or third grade, my best friend at the time had asked me if I wanted to 'play around'. I asked him what he meant by that and he explained that he wanted to get naked, look at and play with each other's genitals. He said he had done it with another friend and asked me if I was interested. I was very modest then and declined. He moved to the east coast not long after that and I never heard from him again. I sometimes wonder what exactly would have happened if I had said, yes.