Frank farts in the classroom and his teacher gets really upset and throws him out.

He goes and sits outside the class and can’t stop laughing. The principle walks by and sees him. He asks, “Frank, why are you sitting outside your class laughing?"

“I farted in class and the teacher threw me out.” The principle asks him again, “Well then, why are you laughing?”

“Because those idiots are sitting in the class smelling my fart while I’m outside in the fresh air."