After reading a few accounts of others first jacking with another boy, I'll add mine.
This happened when I was about 12, and had just begun shooting off although I had been jacking off for about 4 years. By that time, I usually did it 2 or 3 times a day, and if I missed 4 or 5 days, I could do it 8 or 9 times without too much effort because my peter was almost always hard . When I jacked this much, it got a swelling just down from the head which lasted for several hoours and was quite red. The swelling lasted for several hours, and my peter looked burned for a few days. I had been invited to spend the weekend wih a classmate who had a simming pool. The first night of the visit was uneventful, we went to bed about 10, and woke about 7, had breakfast, and then swam. His parents left to go somewhere while we were swimming, and my friend suggested we take off our trunks which we did. He noticed the evidence of my excessive jacking, and said something like I see you jack off too. I didn't deny it, and the conversation led to both of us getting raging hards on. He began to stroke his peter in the pool and I followed. After comming in the pool, we went to his room where he wanted to do it again, but this time he got out a bottle of vaseline. We lubed up and did it again. That night when we were in bed, and I was asleep, I awoke to his lying down next to me and startng to jack again. I did the same. That was a very active week end, but it was so much fun that we slept over most weekends either at his house or mine and worked on our asolescnt peters with great pleasure