This is an old term dating back at least 100 years. My grandmother from Eastern Texas used it quite often to describe an uncouth person. I believe it refers to persons who probably didn't have an out-house or toilet, then when they dropped their pants and stooped down to evacuate their bowels, they would sometime hit the back of their shoes or boots. Of course, they probably just as often hit their pants.
That LeeRoy is a real shit heel.
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