I used to be on the local swim team. One day I got to practice early. No other boys were there yet. I went into the locker room to get changed, I was looking for a looker to put me stuff in. I found a locker that had one of the high school swimmers speedo in it.
I opened my bag quickly grabbed it and decided to see what it was like to wear a speedo. When I got into the stall, I stripped naked and put the speedo on. The thought of wearing another guys speedo gave me a major hardon, so I decided to jerk off in the speedo, and left my cum in it. I then took it off, got changed into my suit and put the speedo back, and went out to the pool and waited for practice to start.