Noun: a dirty scumbag; usually used to describe an individual who has seriously fucked you over. More specifically, it is more of a ramming-your-pants-down-to-your-ankles followed by a repeated anal-insertion-with-no-lube kind of fuck-over. (It's pretty bad.)
What one is forced to do when trying to have sex with an obese female, and does not have any flour handy to roll her in to help search for the wet spot.