Overly assertive girl in back row: Cody, pull up your pants. I can see your butt!
Student #2: You shouldn't say that!
OAGIBR: Why not? It's true!
Student #3: What are you doing looking at his butt?
(Loud peals of laughter from entire class.)
(Side note: anything with the word "butt" in it is hilarious to a 3rd grader.)