I think the phrase when referring to someone or something unattractive it(they) would "Back a houn' off a gut wagon!"

Another when referring to someone leaving an embarrassing scene of sorts, "He(She) ran outta here like a stripe-edd assed ape!"

Overheard in gym class - Bob: "Hey Jim, Ah knew ya smoked, but Ah never knew ya could blow smoke rings outta yer butt."
                                       Jim:   "Uh caint!"
                                       Bob:   "No? Then how come 'ere's nicotine stains on yer drawers?"