similar to potato chips, a very thin slice or small piece of funk trapped betwwen the cheeks of the buttocks.
Butt chips can consit of but are not limited to; tangled butt pubes, lent/fuzz, soiled toilet paper, dried cum, body dander, potato chips etc.
Often smelly, occasionally hard and definitely discusting.
Hottie: "Dude, go put some pants on before you sit down."
Dude: "Why baby?"
Hottie: "Because, I don't want butt chips everywhere."