Holly has a bit of an infection, resulting in occasional toilet accidents...
Daddy: "You know, when you have a poorly bottom, it is a good idea to try to keep your farts in. Because when you are poorly sometimes your farts get mixed up with your poo and it all comes out at once. By mistake."
Holly: "So you mean I need to try to button up my bottom..?"
Daddy: "Absolutely."
Holly: "It's just... sometimes... my poo needs to come out so desperately that it bursts the buttons on my bottom."