When I was younger, my mother signed me up to take swimming lessons during the summer at a gym close by. I didn't really want to, but I didn't have much of a choice.
On the first day, I saw that there were about 6 others there, most were younger, a couple about my age. We were all sitting around in a little room while the instructor was giving us his opening lesson when we found out that the swimming trunks would be provided to us, and that we would all have to shower before we got in the pool. I knew everyone was nervous about that part, just by the looks on our faces.
The rest of the day was just talking and basic swimming techniques, and after a couple hours we all went home. The next day, we were to report to the locker rooms. The instructor gave us all a pair of trunks and said for us to all shower and come back out in 20 minutes. We all didn't want to do it, but we would be in trouble if we didn't, so we stripped off and filed into the showers. Naturally, being young and horny, standing around naked with other people we all had erections. At first, we all just tried to ignore them, but towards the end, the other guy my age asked if any of us ever jacked off. Some of us said that we did, but a couple of the younger ones denied it at first, but after we started talking about it, they confessed that they did. The two of us did it a couple times a day and most of the younger ones did it 3-4, but we were all a little shocked when the other one said he did it about 6 times a day. He had just started masturbating a couple months ago, and he did it every chance he got.
Before long, it was time to get out, so after our erections went down, we put on our trunks and walked out to the pool. The lesson took about an hour, and when it was time to get out, the instructor said he has another class to teach so when we got changed we were free to go, but first take our trunks to the laundry room to be washed.
He was nowhere around, so we all went to that room, took off our trunks and put them in the laundry bag, then walked down the hall to the locker room, all naked except for our sandals. By the time we got to the room, we were all hard again and I was actually dripping precum. I announced that I had to jack off and that anyone else that wanted to should follow me. Every one of us went in and started stroking as soon as we set foot in the shower. One of the youngest was still pretty small and had just started growing hair, but surprisingly, another one of the younger ones was bigger than the rest of us. We asked him how big it was and he told us about 6 1/2 inches, but that he was probably going to get bigger since his brother told him once his was over 8 inches. All this talking really got us horny, and I was the first to cum, shooting it all over the floor. I kept standing there talking to the rest as one by one, white blobs of cum flew through the air. After the last one came, we all went out to get dressed and left, but every day after that, we would all masturbate when our lesson was over. We would even play games, like who could shoot first, the longest, and the most times before we left. A couple times, we stood in a circle and grabbed the guy next to us and started stroking him to see who could hold out the longest.
This went on for most of the summer, but even after it was over, we would still get together every now and then.