Combination stank of swamp nuts/twat, unwashed/wiped ass, armpit, dirty socks, road grime and bad breath producing a funk akin to a bag of rotten potatos. Usually associated with truck drivers that have been on the road for extended periods without a shower.
Shop Planner: what the hell is that nasty funky ass smell?
Parts Coordinator: oh, that was potato butt! that driver never takes a shower!
A person who is being difficult/annoying/stubborn
Stop being such a potato butt!