I find fanny acceptable if not ideal but such a strangely (or not?) difficult question.
dislike words that inevitably make perfectly good everyday objects like fairies, flowers and peaches into euphemisms
find a lot of euphemisms actually a bit more 'saucy' sounding than the more... anglo saxon... terminology
your bottom is at the back
vagina is the hole not the organ
nobody says vulva
am left with fanny!