as in "She's nothing but an old bucketcrutch" is an insulting term which might be a applied to a woman you intend to suggest has had way too many sexual
partners, i.e. she has a crotch
like a bucket
It is horribly descriptive and I'm sure that no man could ever come up with such a shuddersome anatomical reference. I've only ever heard it used by women themselves.
Note: you might think that this should be bucketcrotch, but no, bucketcrutch is the word that I have heard being used.