A persons behind which appears similiar in size and shape to a bucket?, maybe a vessel full of cr..? a giant behind, good-for-nothing except sitting on. Possibly a reference that some one is sluggish? Uncertain of background but an Aussie male I know used it on a regular basis also to people without big behinds. A person which really loves having enormous numbers of oversized penis' being pounded continuously and relentlessly into his anus'; thus extending it and rendering it free and leathery, usually leaking discharge along with other human body fluids, mainly male sperm and puree';d faeces.