ball clapping is when your nuts hit right between your dick and your ass. usually makes a loud noise when hitting, especially when sweaty! Tends to happen during sexual intrercorse, and when jacking off.
When I was screwing this hot chick, I could hear my balls clapping!!!
When you are pail, have very dilated pupils, and probably are sweaty/smelly from rolling at a rave for 8 hours. You cant help but bite on every bitable object in sight and theres no way you're falling asleep for the next few hours. You are clearly fucked up!
Person 1: Wow, I'm rolling balls!
Person 2: Dude, you are completely thizz faced, you smelly etard!