While folding laundry:

Vish: What's this?
Me: This? It's a bra. It's an undershirt girls wear when they grow up.
Vish: What's Dat?
Me: What?
Vish: Dat?
Me: What's dat?
Vish: Um, the boy who lives with us and drinks coffee.

*pause to hide giggling*

Me: You mean Dad?
Vish: Yeah, Dat!