More than anything, they reminded me of my new pup when he was just discovering the joys of humping. Sometimes, my old lady dog would just walk away from his clumsy attempts, and he'd be left convulsing in midair. Being a teenager and a boxer, he is built like those young men and similarly flexible.
Actually, come to think of it, when they were working on the box, they called to mind my sister's dog, whose favorite hobby is to mouth a particular afghan (a throw, not a dog) while languidly humping it. She's a girl dog, by the way.
P.S. You'll all be glad to know that Zach was snipped last Thursday, as I mentioned elsewhere. Unfortunately, he is suffering complications from the procedure (the upside of this is that it allowed me to start a thread called "My dog's scrotum" on another board). It's time for me to ice his groin right now, as a matter of fact.