I was 14 when this happened and it takes place at summer camp in the changing rooms and shower. When I was at this camp we were required to shower daily. I was embarrassed by my 3.5 inch penis and hairless balls. I would always wait for everyone to leave jump in the shower and out again.
One day we had an afternoon event and it required all of us to take showers in the morning at the same time. To make everything move smoothly the councillors made us stand in line to wait our turn which meant not only did we have to shower together at the same time but we had to stand in line naked. I slowly stripped and walked to the line covering my penis. Everyone was joking around and stuff and someone noticed I was covering up. He came over and said move your hands I told him no and before I could react he grabbed my hands and said look everyone we got a baby dick here.
I told him it just seems small. He said ok jerk off in the shower and prove it then. I had jerked before but it was hard to do. I got in the shower and the mean kid was right behind me and said ok show me now. I said maybe you should prove it first. I looked at his penis and it was a good two inches bigger than me. He said ok and jerked off in about five minutes. So then I started and I finally had a boner and the kid started laughing again and said wow did your penis even grow I told him to shut up as I tried to jerk off it took 20 minutes but finally a little bit of cum came out as I orgasmed. The kid laughed and just left. I was so embarrassed.