1.) When your friends at school hate you and don't save you a spot at lunch so you have to sit on the space in between the benches
2.) Under investigation, hiding crack-cocaine inside ones rear in order to avoid its discovery
3.) Two pairs of bare butt cheeks facing each other and making as much contact as possible
1.) Joey: Did you save me a spot?
Isabella: Nope!
Joey: Guess I'm sitting on the crack!
2.) Gabe: The officer was about to search my car, so I stood up, but I was still sitting on the crack.
3.) Aiden: Did you see that "sitting on the crack" video?
Ryan: Oh totally! Where they're touching asses right?
Aiden: Hell yeah dawg!
The act of performing Analingus and chewing tiny holes through the skin around the outer ring of the Anal cavity prior to having Anal sex. Pleasure pain. Extreme Analingus.
My bae asked me if I had any sexual fantasies! And I said "I want to give you Corals on the crack and finish with a rusty trombone."
The act of thrusting the man junk so far into a woman's (or man's if you are homosexual) anus multiple times that the balls consistently slap against the "host's" butt cheeks making a sound like a great high five.
KirtKanReed: "i am soo hungover bro, i can't remember anything about last night."
ChadKant: "you wouldn't want to."
Zenovia's Playa: " YEAH! BECAUSE CHAD GAVE YOU THE sack whack on the back crack WHILE YOU WERE SHIT FACED DRUNK LAST NIGHT AND PASSED OUT ON THE COUCH!"