Using photographed puppets of baby Ernie and Bert, Too Big for Diapers is an instructional book for how to listen to your body when you need to go to the bathroom, and how to conduct yourself when you're there. In this story, readers see that when Ernie was a baby, he wore diapers. He receives a present in a carefully wrapped box --- a new potty. Readers see that now when Ernie has to go, he stops playing and uses the potty. He tries not to use too much toilet paper and makes sure to wash his hands when finished.