Girl: Mom, how did I get out of you?
Me: Um, well, mommies have a little tunnel and--
Girl: Did I come out of your butt?
Me: No, girls have a tunnel between the butt and where you pee. That tunnel is where babies come out.
Girl: I'm afraid a baby is going to shoot out of my vagina!!! [with lots of hand movements towards the ceiling]
Me: Well, yes, that's where the tunnel is, but no, it doesn't quite shoot out, and you don't really have to worry about that.
Husband (interrupting): So, you guys get to go on an airplane with mommy this week!