As an adolescent, I would occasionally join circle jerks with my friends when we camped out.
At times we would sleep out under the stars close to the town common, get silly and about five or six of us would jerk off to see who could shoot the farthest, who had the biggest dick, etc. I, myself never got past the six inch mark and got my balls busted by the guys with the ten inch cannons, but was not as unfortunate as the guys with noticeably less.
My cousin and I camped out together quite often and would get naked during the summer months far away from prying eyes. Not only was his dick much longer than mine, at least a good eight inches long, and a good deal thicker than mine when erect. We didn't always masturbate, but when he hadn't got laid in a while, he was wicked into talking about sex. Not about sex with girls, but about jerking it with other guys.
I always got the idea that he liked sex with guys better than the ladies. Being a few years older than me, he encouraged me to fondle and massage his cock, which I did at first for experimentation. He inferred that handling a larger cock would make me better at jerking my own. I thought to myself, sure it will, you're just a bit on the bi side. I didn't care after I got over the thoughts of questioning my own sexual identity. We would occasionally jerk each other simultaneously, but what I preferred, was when he masturbated himself. It was fascinating to me to see him jerk off. His cock seemed to grow as he proceeded and he would shoot small spurts of pre-cum once every other minute. It would make a juicy lube and watching him shoot so often made me get into myself even more. The pre-cum would get on his arm, on his belly and even on me. Occasionally, he would take some clear juice and smear it on my cock to help me along, as I was usually pretty dry. When he did finally have an orgasm, the flood gates broke loose, and I've never seen so much cum, not even in the porno flicks. After he finished, it was like nothing ever happened. As I recall years later (and many hours of jerking off), it was a feeling like no other to handle such a rocket, though I've not had the desire to handle another.