This happened such a long time ago, but I still remember the events of that day clearly. This is a true story.
When this story happened I was in school in grade 6 and the school was putting on a play/concert combo at the end of the year. I was part of the play along with one of my classmates. This meant that we rehearsed separately from the other kids in the class that were part of only the concert.
Basically how it worked was that be rehearsed during school hours. So when me and the one other guy from my class were busy rehearsing on stage for the play, the rest of the class was going on with new work. When it was time for them to rehearse, me and my friend went to class. But since we were only two, the teacher just gave us the work, explained and left us to our own devices since he was also part of the concert.
So...being left alone when you are in a classroom can lead to many strange things happening over the month with rehearsals going on. My friend who was with me was a notoriously horny person. I remember this because he basically taught every boy in my grade what is sex and masturbation. If it wasn't for his 'expertise' basically none of us would even have known at that age what jerking off was. I have no idea where he got his knowledge from. Maybe porn.
But anyways...like literally the first day we were left in class on our own, my friend got up and locked the door. No explanation. Nothing. He just said: "yes! finally!" and went to the back of the class, got his dick out and started masturbating. Like I am not kidding. He just went for it. No inhibitions. No awkwardness. I stood there and asked him what the hell is he doing, somebody can come back any moment. He assured me it is safe and that he just couldn't hold it in anymore (I guess going a few hours without jerking off was too much for him).
So off he went. I did not join in on that first day. I wasn't in the mood and it was kind off weird. But I was impressed at his manhood. The guy was HUGE. And very, very hairy for that age. I saw him naked the year before at a summer camp, so I knew what he looked like 'down there'. But this was a year later and his development was phenomenal.
I cannot remember if he jerked off every day we were in there alone. We did have some work to do, so maybe not. But it did become a natural occurrence for him to just whip it out and start wanking. But still I did not join in. I continued with my work and by that time he was finished anyway and he copied my work. But on one of the last days I finally decided what the heck, why not.
Being pretty horny myself that day, I took (what was in my mind a courageous step) and told him I'll be joining in today. He said fine, no problem. So being a bit more shy than him, I sat a few desks away and slowly masturbated under the desk. We we're in clear view of one another, but I could not see his dick or he mine. But we could hear each other.
And then something interesting happened. My friend suddenly shouted that he had a brilliant idea. He recently had a quarrel with another boy in class, and he suggested we cum over all his books and pens which was left on his desk. I was close to orgasm, so I thought what the heck, why not. I did not even have that much semen at that age anyway. And I haven't seen my friends actual orgasm up until this point because he always finished under his desk onto the floor.
BIG was my surprise when I joined him at the particularly unfortunate boy's desk to finish our session. We did not touch each other or comment on each others penis. But when my friend came, I could not help myself. He squirted like one, thick, white blob of semen onto the boy's desk. I was gobsmacked. It was the first time I have ever seen semen leave another persons body. He flinched in the orgasms aftermath and milked his (large) penis for every last drop. I came shortly afterwards. Leaving much, much less semen on the desk. He took a piece of paper from the boys exam pad and used it to wipe the last drops of semen from his penis. He handed it to me and I used the other end on mine.
We just looked at each other and smiled.