This phrase was coined by my uncle. He refrains from using more profane wordswith this catch-all phrase. Depending on the tone of his voice it can be used as a replacement for a person's name or just a subtler way of calling you a stupid mother fucker. It all depends on his mood. I have neverheard anyone else but him use this phrase and when I use it around otherpeople they don't know what the hell I'm talking about.
That round head forgot to put the toilet seat down in the outhouse and fell into the pile of shit and piss.