I was with a guy for a long time who never went near his ass crack with a bar of soap. I know, I know, this sort of thing would be a deal breaker if it was readily apparent. But he also went to great lengths to keep me away from his backside in general. When I realized what was going on, it was too late. I confronted him in the bathroom.

"You seem to be neglecting your poop chute. I just watched you suds up everything except, you know, your butt. What's up with that?" I had been brushing my teeth and noting his procedure with mounting disgust.

"It gets clean! The soapy water runs down there. That's all it takes."

"I hate to break it to you, but that's not 'all it takes.' You need to make contact. Here, I'll hand you a washcloth."

"Get out of here."

And it was never spoken of again, although I was very aware, from then on, that I probably just wanted to avoid his butt and his dirty laundry forever.