Slap Ass Friday

An excuse made by teenage boys to sexually assault teenage girls in school hallways. This causes girls to hang their backpacks down low to cover their ass so that boys won't hit them. Nobody likes this except the perverted boys who participate and there are never any repercussions.

Boy: *slaps girls' asses in the hallway*
Girl: You can't do that. That's literally sexual assault.
Boy: Yes, I can! It's Slap Ass Friday!