“That sucks like a bucket full of ticks!”
Ewwwwwwwwwww!
I use that one, and the polite company version: “Well, seduce my ancient footwear”
Dunno where it came from, I first heard in the RAF about 25 years ago.
You can’t polish a turd.
“Too poor to buy a louse a pair of leggings”
“I’m so poor, I can’t afford to pay attention”
“As nervous as a dog shittin’ peach pits”
“Colder than a witches tit”
“As dumb as a box of rocks”
“He has the brains of an ice cube”
“She’s so ugly, she could stop an 8 day clock”
“She’d f*** a snake if it had ears to hang on to”
That’s slicker than snot on a doorknob!
Faster than goose shit through a tin horn.
Well, I’ll be dipped in monkey shit!
Dumb: “Not the sharpest tool in the shed” or “One brick short of a full load”
Skinny: “He’s so skinny he has to run around in the shower just to get wet!”
Old: “Older’n Water” (Or dirt) or “I may be old but I’ll be around to piss on your grave!”
How my boyfriend’s brother spoke of his ex…
“She’s so ugly, it looks like someone beat her face with a bag of nickels.”
On sitting on a too-big chair: “Like a pea on a drum”
On shooting pool successfully: “Gently gently catch a monkey”
On not getting answers wrong in German lessons: “Don’t be a duck-egg”
On Jenga: “It’s gyrating like a disco diva”
colder than the shady side of a witch’s tit in a brass bra doing push-ups in the snow.
hotter than a half-f#ck*d fox in a forest fire
two of my bro-in-laws favorites
It’s as dark as your pocket.
Slicker than deer guts on a doorknob.
Busier than a one armed paper hanger with an itchy back.
hotter than a two peckered billygoat.
Useless as a one-legged man in an ass-kicking contest.
-or-
Useless as tits on a boar.
Slicker than toad snot.
That thing humps up like a show dog (in reference to a chainsaw hitting a knot).
Sweeter than sugar p*ssy.
Brynda - That girl is short up and tall around. That is great! I love it.
When something is especially tasty: That’s good enough to make you kick your grandmaw!
When rain is falling and the sun is shining at the same time: The devil’s beating his wife
Along the lines of “Does a bear shit in the woods?” are two favorites:
Is a fat dog heavy?
Is a frog’s ass water tight?
It’s time to make like a fetus and head on out!
When I first saw this I read lick for kick. I thought it was disgusting but perhaps regionally appropriate. 
Hey!
My mother says the thing about the devil beating his wife.
Another one I remember: You ask someone if they’re serious about something they just said, and they come back with:
“As serious as a bee sting and three heart attacks.”
Good stuff…keep 'em coming. I found heard a translation of an idiomatic expression used in Russia that I thought I’d share while we were at it.
Meaning: “Mind your own business”
Idiom: “If you’re not being F***ed, then stop wiggling your a$$”
(pardon the profanity folks)
“It’s hotter than two rats crackin’ in a wool sock”
leaving: “I’m gonna make like a baby and head out”
the only thing I can think of is
‘thicker than pigsh*t’
-about the most derogatory thing I knew how to say when I was a kid. Also good for describing members of the ARC.
Likewise, ‘dumber than a sack of hammers’.
My dad used to describe trying to make my brothers and I hurry up as ‘herding Brown’s cows’