I still remember!
I was 17 when this happened. I was doing A levels at the time and was invited to stay the weekend with my best mate from our school days. I'd moved to a city away from the rural area I'd lived in since I was a kid and had keep in touch with my best mate. We had a good time that day looking over areas we used to hang out. That night we went to bed after watching a movie and we both couldn't sleep. I was quietly playing with myself, just flicking my cock and teasing myself. I half expected my best mate to be asleep, but he was not! He spoke, saying: are you wanking? I said no but playing with myself. He said go on let's have a look and can you cum? I said: Of course I can, can you? He replied I don't know. He was one and a half years younger.
Anyway he got his cock out and started to play with himself while I watched. I was still playing with myself and had a rock boner (7 inches). His went rock hard (a pure 8 inches!) Anyway he asked me about my technique. I told him how I aroused myself and he tried it. Eventually I popped the question: Let me have a go (I'd always wanted to toss another male off!). I expected him to say no, you gay, but he didn't and so I took his cock in my fist and started to move it up and down. Slowly at first. I could hear him panting and groaning. Slowly I speeded up and I could hear him really groaning.
Eventually I could hear him talking to himself saying that he was experiencing a tingling feeling in his balls. I knew he was about to feel the ultimate orgasm so I started to tickle his balls with my other hand while still moving my right hand up and down on his beautiful 8 inch glistening cock.
Within about 2 minutes he started to moan in ecstasy as his cock got harder and started to twitch-the anticipation of a spunk shower?
I slowed down and held his bell-end to hold it back. He asked me what I was doing and I replied that I was trying to make him experience the first cum (I lived in a city and had a wank buddy there who had taught me what I knew, but that's another story!).
Anyway eventually it got too much and I could feel his cock twitching so vigorously and him groaning and moaning in total ecstasy. His eyes were looking up at the ceiling in total pleasure and so I sped the pace up and oh my god... he erupted. There was so much it was like a huge drip first, followed by a massive fountain of cum all over his chest, in three really big ejections of pure man glue.
I couldn't believe it! There was so much! His cock still twitched afterwards and cum was still creeping out of his eye and slowly moved down his cock stem. There was so much.
Anyway he was so surprised that he'd cum.
I asked him whether he'd wanked himself before and he said yes but had never cum.
Anyway we slept a lot better that night and have never talked about it since. I still keep in contact with him and his wife and three children.
But... I still remember that night! I know he does too!