I visited Poland a few years ago and whilst there I decided to go for a swim at the local pool.
I entered the pool and paid my entry fee and asked for directions to the changing rooms, I think I must have misunderstood the reply.
I went to the changing rooms which were open plan and had no one in there and proceeded to undress.
I was standing there totally naked looking for my trunks in my bag when I heard voices coming into the changing rooms, and they sounded very female.
Then they entered the changing rooms and sure enough it was a group of school girls that had been there for their swimming lessons, and was greeted with the sight of me standing right in front of them fully exposed.
They were all dressed in their bikinis and very pretty and I got an immediate hard on forgetting that I was naked until one of the girls pointed it out to me amongst all the giggling and screaming from the girls.
Luckily I was told were to go and didn't get into any trouble.