Is that a mole?

Here's a recap of a conversation between Jack and Grandmommy that took place this evening. He was sitting in her lap visiting, and I almost had to leave the room because I was laughing so hard.....

Jack: What's that? (pointing to a mole on Grandmommy)
Grandmommy: That's a mole
Jack: Do I have any of those?
Grandmommy: I don't think so. I think you have a birthmark.
Jack: Look, I do have one. (Lifting his shirt and showing her a nipple)
Grandmommy: Well....that's not a mole.
Jack: What is it?
Grandmommy: It's a nipple.
Jack: Sometimes I pull on my nipple....Grandmommy, do you ever pull on your nipples?