Conversation with O
O: Let's play a game. You be the mama, and I'll be the tooth fairy. I will fly around and give everybody gifts.
Me: What's a tooth fairy?
O: A tooth fairy is someone who gives people gifts.
Me: When does she give gifts?
O: At night.
Me: She gives everyone gifts every night? That's a lot of gifts. I bet she gets tired.
O: Yeah, but she's a fairy.
Me: Why is she called a tooth fairy?
O: Cause she can fly.