This story happened when I was 13-14 years old, somewhere around there.
When I was in my early teens, my family took a trip out of town for a wedding. We took my mom's minivan, and my mom and her friend rode up front while me and my friend, who was about my same age, rode in the back. We had packed like we were going to be gone for years, so the back of the van was piled high with stuff. And with our parents talking loudly and playing their oldies music, we had a fair amount of privacy in the back of the van. Up to this point my friend Mike and I had never messed around, although we talked about sex sometimes, and when we spent the night at each other's houses, we always slept in our underwear (though I don't think we'd seen each other naked yet).
Anyway, in the back of the van we talked and horsed around and played with our Gameboys (anybody remember those?) and just in general were having a great time. It was a really long ride to the town we were going to, but we were hyper and having a great time. I don't really know how it happened, but in the course of messing around we started grabbing each other's cocks through our shorts (it was summer). It was just playful at first, but after a few times we started getting erections and we got more serious. Even a little nervous, I think. We were in uncharted territory, and that was exciting. Not to mention that our mothers were just a few feet away, and if they had known what we were doing we probably would have gotten scolded. Mike's mother was very religious and would not have been too keen about that. We rubbed each other for a few minutes, then stopped for a while and started playing with our Gameboys again. There was an awkward silence between us for the first time that trip, and I knew that he was thinking about what we'd just done too.
Then I felt his hand on the waistband of my shorts, and suddenly his hand was down my pants. I still had my underwear (white Fruit of the Loom briefs, of course!) between my cock and his hand, but I just about jumped through the roof of the van anyway. I hadn't been masturbating for more than a year or so, and it didn't take me long to cum. I thought I was going to explode right there. Then he started rubbing his hand up and down on my erection. What a feeling! To distract myself a little bit, I reached over and stuck my hand down Mike's pants and started fondling him as well. I think Mike was even hornier than I was, and within less than a minute he grabbed my wrist and stopped me from stroking him anymore. He later told me that he didn't want to cum in his underwear and be sticky for the rest of the trip. So for the rest of the ride we passed the time talking about ordinary things and playing video games, although I was horny as hell and could think of little else than what we'd just done.
When we reached the hotel, we still had several hours left before we had to start getting ready for the wedding. Mike and I were sharing a room, and our mothers were in a room a few doors down. I was excited, thinking that we'd probably masturbate each other again. We decided to go swimming in the hotel pool, and we got changed into our swim trunks in the hotel room. That was cool because I got to see Mike naked for the first time. He had a nice body, skinny but fairly muscular at the same time. And he had a small patch of pubic hair, and his cock was about the same size as mine. We went swimming, and when we got back to the room we each took a shower and then lounged around the room, me in my underwear and Mike in shorts with no shirt on. It was fun, but I was bummed out at the same time because Mike had made no move to continue the fun from earlier. And we'd been practically naked in front of each other for over an hour, and I felt that if anything was going to happen it would have to be then. And I certainly wasn't going to make the first move. If anyone was going to make the first move, it would be Mike, and he was acting like nothing had happened. Pretty soon we had to get ready for the wedding, and I pushed it out of my mind. We went to the wedding, then the reception in the hotel ballroom, and didn't head back to our room until close to midnight. All the adults were still downstairs drinking, so Mike and I walked back just the two of us.
'Do you remember what we did earlier?' Mike asked hesitantly when we were almost back to the room. It had obviously been on his mind as well.
'What do you mean?' I asked in return, trying to sound casual. Of course I remembered!
'You know, in the car,' he said, avoiding coming out and saying it.
'Oh. That. I remember.'
'That was fun. Do you want to do that again?'
'Sure,' I answered casually, though my heart was about to beat out of my chest.
When we got back to the room, we stripped off our ties, then our dress shirts and pants. Standing there in our underwear, we grinned at each other nervously, looking at each other's erections.
'Should we take off all of our clothes?' Mike asked, and we did, stripping off our underwear and standing there in all our glory. After it became obvious that I wasn't going to move, Mike walked over to me and took my hard cock in his hand. He wasn't stroking it or anything, but it was the first time anyone had touched me there, skin on skin, and I almost came right away. I grabbed a hold of his penis, and noticed how different it felt from holding my own, even though they looked practically identical. We stood like that for what seemed like a long time, then Mike started moving his hand up and down my shaft. I copied his motions, and soon we were furiously jerking each other off. Mike started to make little noises and thrust his hips forward in small, involuntary motions. And I'll never forget his facial expression. His eyes were half-closed, and he looked to be in tremendous pain. I'm sure I looked equally silly.
'Oh man!' Mike cried, and threw his head back as he started to orgasm. His cum shot onto the carpet between us as I continued to stroke him rapidly. Luckily he had the presence of mind to continue to stroke me even as he orgasmed, and soon I followed and had my own powerful orgasm, even shooting some cum onto his stomach and legs. We were breathing like we had just run a marathon, and my knees felt like they were going to buckle. After we recovered a bit, we stood there grinning at each other, still holding our cocks.
'That feels a lot better than doing it yourself,' Mike observed, panting.
'So you jack off?' I asked, though the answer should have been obvious after the expert handjob he'd just given me.
'Every day.' he answered proudly.
And that was the end of any inhibitions that there were between us. We talked about masturbation well into the night, and jacked each other off three more times. We had many more experiences like that after that trip. Maybe I'll tell those stories here sometime.