you wanna bet i'm not...?

Wife: Stop touching my butt.
Boy: Why?
Wife: Because you don't touch other people's butts. Remember in the store today I told you to stop touching my butt?
Boy: But I was trying to keep up with you.
Wife: That doesn't matter. You don't touch other people's butts in public.
Boy: (pause) What about my own butt?
Wife: If you're polite, you don't talk about or touch butts in public at all. Not even your own.
Boy: Come ON, Mom... you are NOT in charge of my butt!