In high school I played on the baseball team. Usually after a practice everyone showers off and leaves when they're done, but one day I stayed afterward to work a little more on my fielding for about a half hour. When I was through I went to the locker room and stripped down and went into the shower room. I expected to be the only one there, but when I walked in I saw three guys in there from the soccer team, all naked and jerking off. I knew who they were, but didn't really know them because they were in different classes. When they saw me they all stopped and stared, but when I turned around to leave they stopped me. I asked why and they said since I caught them, I had to join them so I couldn't rat them out. I really didn't want to, but there were three of them so I didn't really have a choice. I walked over by them, forced myself to get hard and started masturbating along with them.
Nothing much was said, I guess because I was new there, but the room was full of heavy breathing and a moan here and there. The whole time I kept thinking it was wrong, but at the same time I was a little into it because I had never done anything like this before. It felt like forever, but one by one they grunted and shot thick globs of cum on the floor, then stepped back and shook their penises and flung out the rest. When they were finished they all watched me as I stroked myself. I knew I had to cum so I closed my eyes and started thinking about porn I had seen before, and pretty soon after I leaned back and shot a huge load straight out. My whole body was shaking as I squeezed a few more drops out, and they said now if I told on them they would tell on me, but they usually did it after all their practices and I could come back if I wanted to. They then started showering like nothing happened, and I did too.
It felt kind of weird after that at first, but eventually I wanted to do it again, and the next time our practices overlapped, when I went in they were stripping naked. We talked for a couple minutes then went into the shower and masturbated. This went on for a few more weeks until the season was over, and then I lost all ties with them. I don't know if they did it again the next year since I didn't try out for a team, but it was kind of fun while it lasted.