I used to hang out with a couple of friends, call them Rick and Trevor. Rick was about my age, seventeen at the time, while Trevor was a year younger. We planned a canoe trip of several weeks that summer and decided to take along just one big tent for the three of us to share. After a couple days it became apparent that, as horny teenagers used to wanking regularly, there wouldn't be any privacy to masturbate unless each of us snuck off into the woods alone.
The third night as we were getting ready to settle into our sleeping bags, I was considering it, when Rick pulled several porn mags out of his pack and also tossed one to each of us. He said he needed to jack off and thought we probably did too. We'd joked about wanking and seen each other's penises in the gym showers. So why hide it. He got comfortable, unzipped and started rubbing his dick through his shorts. Pretty soon we all had our hard cocks out and were working away on them. Rick's cock was the biggest at well over seven inches but Trevor and I also have fairly large penises. That first night we just pumped away on our own until spurting our sperm. Later on we started comparing and stroking each other's cocks, seeing who could shoot the most semen, and so on. It was a memorable trip.