Dogs and Goats! Riding Each Other!
ride the goat. To be initiated into a secret society; --from the idea that a goat is sometimes used in the proceedings.
I couldn't come up with a poem about it, but the phrase stayed in my head for obvious and disturbing reasons.
Today, under similarly random circumstances, I wound up reading about Mr. Cassius Coolidge, the artist who created the original "dogs playing poker" series back in the 1870s-1880s. And I found THIS picture:
It's called "Riding the Goat." Dear god. I can already feel the nightmares brewing.
P.S. If you can't see the picture on your browser, here's the link to DogsPlayingPoker.org. Click on Gallery, then on Cassius Coolidge. Try not to look directly at the screen.