Comes from early 30's to describe a "hick" or "backwoods" negro man. Also used to describe poor individuals living in the ghetto or slum neighbourhoods. Related to people on the welfare system.
Bwoy, I say bwoy, you better git your poedunk nigger ass off mah fuckin' lawn before I shoot chu.
Yo dawg, dun be gettin' raged cuz of dat poedunk muhfugga, look, he wearing Exco.
I bet dat poedunk coon piece of shit lives wit his mommy. Poor ass welfare muhfugga.