Actually, that is the wrong answer. The right answer is Jules to Vincent while they dry their hands off in Quentin Tarantino's character's house. Jules dries them off without messing up the towels, while Vincent does it haphazardly and gets the towels all stained.

Anyway, I'll answer your new question and put a new one up.

A: Jules to Vincent while cleaning up the car in the garage, referring to the fact that Vincent should be in the back, cleaning up the mess that he caused.
Q: "I'm a mushroom cloud layin' motha fucka, motha fucka!"