Me: No, remember we talked about this before, buddy. That's not a pocket in your underwear.
F: What's it for then?
Me: [quietly explains the purpose of the opening in underwear]
F: So... It's a peepee pocket.
Me: No, that's not-
F: I have a peepee pocket! Peepee pocket! Peepee pocket!
Me: *sigh*
F: [runs out of the room] peepee pocket! Peepee pocket!
Me: Just... *sigh*