Pooped out

Sidamo just discovered, to his great delight, the phrase "pooped out." He heard it in a Toot & Puddle book and couldn't stop laughing. Now he keeps trying to recreate it but can't remember exactly how it goes. Instead he has been saying, "Are you knocked out of the butt?" So very close. Feel free to use it if you're so inclined; I'd love to see his rendition enter the vernacular.