'Bucket' is a commonly used term describing a wide vagina cuased by a lot, and I mean A LOT, of sex. Usually used as an insulting term, but some women seem to be proud. When explaining the term 'bucket', some people tend to use the anecdote 'like throwing a sausage down a corridor', which means a penis (the sausage) going into a wide vagina/bucket (the corridor).
Guy 1: Damn, that girl's hot.
Guy 2: Mate, I wouldn't. Loads of people of said she's got a bucket. Imagine throwing your sausage down that corridor.
Girl: Don't talk about my bucket like that! I'm proud!