As small children, everyone I knew had names for their genitalia, usually something boringly simple like "willie" or "tail" for the boys, but the girls parts got far more exotic names like "fairy", "foo-foo", "tuppence" or "twinkle".
I must confess to having something of a problem using the word "vagina" to my six year-old (I'm not sure why), but equally I can't stand all that "front-bottom/back-bottom" nonsense!
Fortunately it's not a regular topic of conversation at our dinner table (yet).