After a long and fruitless research despite [@flopsi]'s kind help, I turn to benevolent native speakers to pierce the mystery of these powerful words of wisdom:
I appreciate the way you watch me, I can't lie
I drop it down, I pick it up, I back it out the county line
I fell from heaven, now I'm living like a devil
You can't get me off your mind
I appreciate the way you want me, I can't lie
I drop it low, I back it up, I know you wanna think you're mine
I repeatedly prayed to the Google God, browsed quite a few UD entries and went sightseeing through all the song meaning resources I could think of.
I collected a lot of weird sexual code words and a few peculiar meanings to "county line", but was left none the wiser about the intended message. Not even what the "it" might stand for, if it stands for anything.
What struck me as odd is, nobody on the Internet ever seemed to wonder about these lines. As if backing whatever-thing(s)-you-can-back-out-the-county-line out the county line was such an obvious thing to do.
I'm bracing for the blinding flash of the obvious. Thanks in advance.