On a hot day, a couple summers ago (when me and my friend were like 13) we had just bought a pool, and it was just finished filling. We weren't doing anything that day so my mom asked me if I wanted to ask one of my friends over to go for a swim. I called him (I'll call him Simon) up and he said he'd be over in like 15 minutes.
When he came over, we swam for like an hour-and-a-half or two hours. We eventually got out and went into the basement to play video games, etc. We started going onto the computer, and wanted to talk to friends online. When I started up the computer and finally got logged on I first checked me e-mail. I ended up getting on of those porn e-mails where the subject doesn't really tell you what it is so I opened it. As most guys know, air conditioning + damp bathing suits + naked chicks = arousal. It was obvious that both of us were hard because our bathing suits were tenting. We also both put our hands inside our suits and started jacking off. Now I was sitting in front of the computer and he was off to the side, but we could easily see each other. Neither or us were gay, just curious. I showed him one of the sites (I actually think it was this one) that I usually get off to. Just then my mom yelled down the stairs that she was going to pick something up, and she'd be back in like five minutes. We continued with what we were doing, and eventually Simon 'flashed' me by pulling down his suit. Fooling around I said, 'Is that it?' He said he quickly wanted to see mine, but I was hesitant. I eventually gave in and showed him. I'm not one of those people that say that they are huge or anything, I think I was maybe 4 or 5in during this event. He was maybe two or three inches. It caused him to just say wow.
My mother soon returned and all she did was yell down the stairs again, saying she was home and she got lunch. We quickly scarfed it down so we could go back downstairs. We both agreed to pull our suits down so we could 'look at each other.' I guess I was further through puberty than him, because I had more pubic hair then he did. After a few minutes or staring at each other my mom came down to grab some stuff for dinner. Luckily we were able to pull our suits up, and made it look like we were watching TV. After that we agreed to go to a more hidden area. The only other place we could think of was in some really dense woods in my backyard. (Don't worry, it's not like we were really dumb and went to a set of woods where people would be able to see us.) It wasn't that unusual for us to be in the woods anyway, we often went back there to make paths, etc. On the way out, I grabbed a container of Vaseline.
When we got into the woods, we completely stripped our bathing suits off and rubbed ourselves a little to get hard again. Both of us took some of the Vaseline and started jacking off. It felt weird having someone there while I was masturbating, but not in a bad way. He came first and then me, but neither of us grew soft. We put our bathing suits back on, and grabbed our t-shirts and thought we would go up the block and see what the neighbors were doing. Fooling around again, I said how noticeable my semi-hard penis was through by suit, and how un-noticeable his was.
As we walked up, we saw (I'll call her Jessica [also attractive :-) ]) playing with a bunch of other younger kids. Neither of us had seen a real naked girl before, and wanted to see one... But that's another story!! :-D