A bit of teaching.
Although I am now a senior in high school, this incident happened back in the seventh grade. I had started masturbating successfully the summer before, when a friend mentioned to me that it takes longer than 15 seconds to achieve orgasm. I was pretty developed by this point, with plenty of pubic hair and the beginning wisps of armpit hair. My penis was already almost fully grown, about five inches in length and a width above average (according to my camp bunkmates, about an inch in diameter).
Anyway, it was a Friday and my friend James was coming over to hang out. He was also in seventh grade with me, but was much smaller and less developed. Being seventh graders, we didn't have much to do that would be considered social, so we hung out in my basement and went on the computer. I had gotten a spam porn email that day, and opened it as a joke, but James grinned awkwardly. Being horny myself, I offered to show him a video that I had found (okay, so it was my parents'...but I try not to think about that) to see something more interesting. He seemed a bit giddy and complied.
We went over to the couch and I put in the video, which consisted of 2 guys and a girl. I instantly had an erection, the bulge from which I didn't necessarily hide. 'Jeez that thing is HUGE,' James said. I laughed and said that it was about six inches (a bit of an exaggeration, but anyway). I could tell he was curious, but out of nowhere he reached over and touched it through my jeans. He kept saying things about how big he thought it was, and so on.
I offered to show it to him, and after he said the obligatory 'promise not to tell?' he excitedly agreed. I pulled my jeans and boxers down to my knees and gave him a good look. I definitely felt cool having such a bigger and more developed penis than he had. Not wanting to miss out, however, I suggested that he pull his out too. After a little convincing ('it's only fair...you've seen mine') he did.
I can't say I was impressed--although that's not what it was about--but he had a three-inch, very hard, VERY skinny penis. There was just a fuzz of pubic hair above the base. 'Do you masturbate?' I asked. 'Sometimes,' he replied, although I got the feeling that was a no. I played along, and suggested that we masturbate then while watching the movie.
He didn't start masturbating...nor did he start watching the movie. He just stared in awe while I pumped my dick with my right hand. Seeing that he was definitely interested, and that he was also not doing too well with regards to his own member, I suggested that we try playing with each other's dicks. He seemed a bit hesitant, but agreed, and almost right after I grabbed his, he reached over for mine.
I was naturally pretty used to my own penis, so his seemed ridiculously small in my hand. I didn't mind however, and moved my hand slowly up and down. He had no idea what he was doing with mine, and just sorta rubbed his hand around it. I started to ooze precum, which surprised him, and he took his hand away. As a courtesy I removed my hand as well, and went back to my own penis. I had enjoyed exchanging dicks much more than I had anticipated, however, and this set off the spark that led to a few more mutual encounters during my teen years.
I asked if he could cum yet, and he said no, so I asked if he minded if I ejaculated next to him on the couch. He said he didn't, and seemed once again completely interested in my masturbation. I was turned on by having such an interested viewer, and grabbed a bunch of tissues. Holding the tissues in front of my throbbing head, I let out about five streams of cum to James's amazement. Not being able to do much else James stopped as I did, so that was it; but I sure enjoyed it.
Although that was the only time we ever masturbated each other, we stayed friends through middle school and masturbated in front of each other one other time. He still couldn't cum, but a few months later he told me that he did. Although that wasn't the only mutual experience I have, it was certainly fun to be able to teach a friend about what he was missing.