Where Does Poo Come From?

Now I know that a lot of people are going to have a stab at this poo query and, perhaps, say Birchington.
But you'd be wrong!
A friend of mine was asked this question the other day by her five year old daughter. She took great pains to describe the workings of the human digestive system in detail and was met with a rather disgusted "YUCK! So mummy, where does Tigger come from?"