Just to clear up the fanny business, that is something my dead grandmothers would say. It does mean "ass" I just say ass or butt, usually ass. I think fanjo is my new favorite word by the way. I don't like American slang for vagina because they're all so vulgar (pussy, cunt, twat) writing it makes me cringe. Saying vagina is too clinical, fanjo sounds funny to me.
Just while we're on the subject. I loved giving birth. I loved it. I would do it a million times. You have such a deep connection with your body, and it is so amazing how your body just knows what to do. I'd never pushed a baby out, but my body knew what to do. I didn't think about I just did it. Yeah it hurts, but it's the good kind, where you're scared, amazed, and happy all at the same time.