innie and outie

As I drove, with Liz sitting shotgun, the boys were having a discussion in the backseat of the car.....

Roberto: I have an innie.
Brad: I have an outie.
Roberto: You do? No you don't.
Brad: Yes I do. I'm an outie, like you.
Roberto: But, I'm an innie.

At this point Roberto looked over at his brother, curious. Wondering what Brad was talking about.

Roberto: Do you even know what we are talking about?
Brad: Yeah. Innies and outies.
Roberto: But do you know what that means?

Brad starred at him for a minute. Confused. Wondering what Roberto was talking about.

Roberto: You don't do you? You don't know what we are talking about.
Brad: Vaginas and penises?
Roberto: Oh, my gosh. No. Innies and outies are the kind of belly button you have.

We all laughed. All at once. Me. Liz. Roberto. And then Brad.