Southern US slang is sweet as pecan pie and twice as rich. These folks turned politeness into an art form where "bless your heart" can be the nicest or the meanest thing you ever heard.
Bless your heart
This can mean "you're so sweet" or "you're an absolute idiot" and you'll never know which one. The ultimate Southern double-edged sword, delivered with a smile that reveals nothing.
Finna
Fixing to, about to, going to. It's "fixin' to" compressed even further because the South values efficiency in speech (if not in pace of life). Action is imminent when finna appears.
Cattywampus
Crooked, off-kilter, not straight. When something's cattywampus, it's gone diagonal on you. The picture frame, the parking job, your cousin's life choices, all potentially cattywampus.
Plug
A connection, a hookup, someone who can get you what you need. Your plug is the friend who knows a guy who knows a guy. It's social networking, Southern style.
Yonder
Over there, in that direction, some distance away. Southern folks point to the horizon and say "over yonder" with a vagueness that could mean next door or three counties over.
Scooch
To scoot over, to move a tiny bit. It's the polite Southern way of asking someone to make room. You don't shove, you don't push, you scooch. It's movement with manners.
Ace up
To perform brilliantly, to absolutely nail something when it matters most. When you ace up, you rise to the occasion and deliver beyond everyone's expectations.