Mechanical asshole

I don't think I've told this one yet. First, let it be known that I never swear around my son.
We were watching Dirty Jobs, and Mike Rowe was helping out at a place that turns poo into flower pots, or something like that. Mike announces that this particular machine that forces out the poo was like a big mechanical butthole. My aunt Tina came over a few minutes later, and the machine is shown on tv again. Jaren says, "Look Tina, this thing is a big mechanical asshole."