Noodle: "What if I have to go potty while Santa's here?"
Me: "You just go straight to the bathroom same as always. But no peeking down the hallway."
Noodle: "But what if Santa has to go potty?"
Me: "He always makes sure he goes potty before he leaves the North Pole."
Noodle: "What if the reindeer have to go potty?"
Me: "They wait until they're flying over the ocean so they probably won't hit anything."
(Yeah, YOU try coming up with a better answer in a snap in that kind of situation.)