I have heard it used numerous times in NC. I am pretty sure that it was even used in a political ad by one of the Senate candidates last year.
What about “in a coons age”? For example, “I haven’t seen him in a coons age”. I hadn’t heard that one before my wife used it. When I used it in front of my brothers they both thought I had lived in the South for too long.
The way I read the story is that if the police officer insists on knowing how the “cow” is eating the cabbages, she’s eventually going to have to say “It’s sticking them up its ass.”
She doesn’t want to say it, and won’t be happy to have heard it – but it needs to be said, all the same. 
I just read a new one this week!
A colleague started a discussion thread with the subject line:
I love this stuff.
But I never once heard the question “Are you a turtle?” until I read this post. I still can’t figure out where I was supposed to have heard it otherwise.
I had a friend who always said “sort of speak” when he meant “so to speak.” Made me cringe every time.
I have a ton. I once had an ex girlfriend who had never heard of the phrase doing something “like it’s going out of style”…for example “Wow, you’re eating those chocolates like they’re going out of style”.
Behind a spoiler since it may be TMI:
I have another very close friend who didn’t know what DP meant when used in a sexual way. And while I can understand being a little innocent, she’s almost 30. I thought that DP was a bit more common knowledge than that. (She also didn’t have any idea what a facial was, in the sexual sense)
I use the phrase “I’m not gunning for it” a lot, but that’s seemed to fall out of being well known or even known at all.
And lastly…I’ve had a total of three people look at me strange when they’ve said something I’ve agreed with and I replied with “And how!”. Two of them asked “and how what?”.
Does nobody use “And how!” that way anymore?
I use a few that seem more obscure, but probably more recent and sound better in a hillbilly accent: “Busy as a cat in a sandbox” meaning “too busy to take a break”, and “Tell (someone) where the bear shits”, meaning to lay down the law or issue an ultimatum.
"That really gets my goat"was a favorite expression of my father. He also cautioned against letting people know what irritates you, as “It’s easy to get your goat if you let everyone know where it’s tied.”
When I first moved to Philadelphia, I mentioned that something was “all the way out in BFE” and I was surprised that no one knew what the hell I was talking about.
Cripes!
I would have gotten it from context, but I’m more familiar with BFN, buttfuck nowhere, Buttfuck, Alberta, the ass-end of nowhere.
Occasionally I’ll come across someone who’s not familiar with “metric fucktons” or “a metric assload.”
Finally, until recently I had no idea that the phrase “elbow grease” didn’t mean a certain kind of grease.
Here’s one from about ten years ago that put egg on my face.
I was working at a nursing home and feeling pretty tired one day. A co-worker was behind me and we were chatting whilst ambling when she said “You’re a litt;e pokey today”.
Me: :dubious: Huh? I haven’t touched you, let alone poke you. I have no desire to poke you at all. Why are you spreading these vicious rumours about me? I have not harassed anyone!
What I actually said was “Pokey? Huh, wha”?
Co-worker: Pokey, you know, slow. You never heard that before?
Me: Uh, no.
CW: Really?
Me: Uh, yeah, really.
And I hadn’t. No one I knew has ever said “pokey” to mean slow.
“Delaying the Eschaton.”
My new slogan.
When I first relocated here from NYC, I once said “I don’t give a rat’s ass!” and got some very strange looks. It was a fairly common expression in New York; by now I think it’s common everywhere.
The pokey little puppy and his rolly-polly brothers would like a word with you.
My Mom—“Hot Dog and a Pickle!” when she’s excited
My Dad–“Christ on a Cracker!” usually when he’s broken something
I worked for a guy who knew several phrases for any given situation but would always end up mixing them when speaking. So he’d say something like “Let’s not work on that right now, we don’t want the dog wagging the cart.”
I’ve had to explain “spitting feathers” (“thirsty”) a few times. Apparently it’s only common in the north of England?
I remember when Siskel & Ebert reviewed this on their show. I’m pretty sure it was Ebert who mentioned this phrase and said he had no idea what it meant. He also couldn’t tell whether Rourke was saying parker or porker.
Apparently, Kermit the Frog isn’t quite as popular as he once was, because nobody seems to like it when I greet them with “Hi Ho”, which I borrowed from Kermit’s Sesame Street News Pieces * (“Hi Ho; Kermit thee frog here for Sesame Street News”)*
An old girlfriend was completely insulted when, after a long day, I commented to her, “Boy are you a sight for sore eyes.” She could not grasp this as a compliment. I explained it over and over but she was still upset. Dumb B-tch. 
I actually use a lot of phrases mentioned in this thread, and have never gotten any flak for them, except once recently when someone raised an eyebrow at my use of “cat’s pajama’s.” I was taken aback by his being taken aback by the phrase. Now what’s all this about being pecked, picked, nibbled, or otherwise attacked by ducks? This is something I’ve never heard of until just now.
HA! This makes me laugh quite a bit.
Idle Thoughts: the phrase you put in the spoiler, which I won’t mention here since you hid it–I’ve never heard of that, either. Now I’m curious as to what it means.