What are two things you could call a fart?
"Gas from the ass" or "Odor from the motor!"
Okay, so listen up, because this one's a thinker for dummies like you. Basically, it's saying a fart can be called "gas from the ass" which, duh, is where it comes from. But then it gets clever and calls it "odor from the motor," which is like, a funny way of saying your butt is an engine making stinky smells. You probably drive a Prius.