Your big bum

As Thomas was doing a number two on the toilet tonight, he asked me an interesting question--

Thomas: Mama, why do you weewee with your big bum?
(I think he was asking why I didn't pee standing up.)

Later on, as I finished helping him brush his teeth--

Thomas: Mama, I think I have a cavity. Right here.
Me: That's terrible. We had better make an appointment to see the dentist.
Thomas: What's her name?
Me: Dr. Ivy.
Thomas: No! I don't want to see Dr. Ivy. I want to see a superhero dentist! With a superhero out the window.