Keep a lid on it

Boy: Have you heard about bottom lids?
Me: Errrr. No.
Boy: Well, unfortunately, you know some people have a chemical in their bottoms. And they need to filter it out.
Me: Right.
Boy: So they need a bottom lid on their bottom. To filter out the chemicals.
Me: Oh.
Boy: And they have to keep it on for TWO days. And they have to strap it on over their bottom cheeks.
Me: ......
Boy: Do you want to see a picture of someone with a bottom lid that I drew?

.... do you?