Bottom problems

The cat had some bottom problems. Specifically, there seemed to be blood coming out of it, which seemed kind of serious. So I rang the vet.

"The cat's bleeding out of her bottom." I told the person who answered the phone. "Bottom of her what?" They replied.

"Bottom".

"Bottom of her foot? Bottom of her head? Bottom of what?"

I was flummoxed. What could I say? Arse? They wouldn't understand. I felt like Borat, and wanted to say "ah-noos".