Conversations in a public restroom

This is how it goes. Helen is in the restroom stall behind the closed door. I am outside waiting for her--meaning that I am face-to-face with other patrons as they come and go. Because we are usually in there longer than anyone else.

Helen: "Did ya hear that?"

Me: "Um, yes." or "No." or an ambivalent "Hmmm?" [I know where this is going every time, but I haven't yet figured out the response that will head it off.]

Helen: "I tooted!"

Me: "Mmmm." or "OK." or whatever else I can think of to mumble, still hoping that the conversation will somehow stop there. It doesn't.

Helen: "But I didn't say 'excuse me'!"

Me: "OK."

Helen: "Because I'm in the potty. And it's okay, we can toot in the potty. So we don't have to say 'excuse me' when we toot and we're in the potty."

Me: "OK. That's fine."

Helen: "But if we toot and we're not in the potty, we're supposed to say 'excuse me.'"

Me: "Yes."

Helen: "We can say 'excuse me.' But we can't say, 'Excuse me, you're biting my butt.'"

Me: "Right."

Helen: "Because then we can't watch Madagascar any more."

Me: "Right. Are you finished yet?"

I have had this exact conversation at least eight times over the past few weeks. The only thing that changes is how many people overhear us and how many of them start laughing.