Girls only, this boy had a nice bum?

This is a funny story but true. Today i went to the swimming pool to have a lesson in a group with other girls. After we finished, we walked to the changing rooms, to do that you have to walk through a narrow corridor, and we stopped when this teenager, about 18, was bending down sticking his bum out. We couldn`t get through because the corridor was too narrow, so we all were just laughing and he still didn`t move. One of the other girls said excuse me, and he still didn`t move. When we said excuse me again he stood up. We were staring at his bum and he had a nice bum! I wanted to smack his bum or pinch it. Should i have done that, baring in mind that he wasn`t getting out of the way when we said excuse me? It was so funny!!!