This was the first time I masturbated outside my house. I used to take swimming lessons, and I always feared getting an erection in the pool. I had many friends there, so it would have been a embarrassing. But at the age of twelve or thirteen when puberty begins, and especially when girls begin to grow, and they wear swimsuits...well, you get the idea. Most of the time, cold water and a bit of concentration were enough to get rid of these feelings.
After the lesson we had to take a shower, but the boy's showers were separated from the girl's showers. It always ended up into shampoo battles and other stupid things that little boys do.
Anyway, after showering I dried myself and got dressed in a closed cabin. I always felt quite worried about anyone, even friends, seeing me naked. The good thing about these cabins is that they are really intimate. The thought of all those nearly naked girls always entered my mind as I was rubbing myself with my towel. The walls of the cabin were a kind of ceramic tile, so I decided it was a good private place to masturbate.
It was a real pleasure to do this, especially when feeling really tired from the swim lesson. It's difficult to describe the feeling when you're tired, you have a very small dick due to the cold water, yet you get aroused because of all the nice girls with breasts all around you for hours. My penis was always very 'hot' in my hand.
I usually cleaned up my penis with my swim pants, and I always left my cum on the walls, even though I felt strange about the next person coming in and discovering my cum dripping down. But it felt so good each time! Since that first time, I always masturbate after I go to the swimming pool.