We are riding quietly in the car when suddenly,
Calliope: Vaginas are more relaxing.
Me: Ah. Um. Well. What makes you say that?
Calliope: Because with a vagina you get to pee sitting down. If you have a penis you have to pee standing up. That's more tiring.
Me: Ah, I see.
Calliope: That's why vaginas are more fun.