How do you wear sliding shorts with underwear or no underwear?

My friend Peter is very weird he doesn't wear underwear all the time. In after school sports he doesn't wear underwear under his shorts. He gave me this reason: Don't you not want your balls to get your undies all sweaty and that you have to let your balls be free. He showed me his balls once @ a sleepover. They weren't ugly although he made me stare @ them all night. We slept in the same bed and he made me undress so he saw my balls. He said they weren't ugly either. Peter is very perverted. He kept touching my balls and hugging me in bed. It was actually kinda fun.