Dumping holding tanks explained... Sorta.

When my daughter was about 4 - 5 years old she asked where the "stuff" in the toilet went. We lived in a ranch style house with a full basement, at the edge of town with city water / sewage / gas. I took her in the basement of the house and showed her the pipes under the floor going through the wall of the basement, underground to the street. From the street, we followed the line and took a little road trip to the city sewage plant. We did not go inside, but by now, she got the message and was completely thrilled with her new-found knowledge.

I think explaining the trailer holding tank and dumping procedures would have been easier. Now, if she asks where the contents of that "stuff" goes once it goes in that pipe in the ground .... face it ... you're in trouble!