Sticks like shit to a blanket. (charming grandmother I had)
If pigs could fly and elephants wore high hats.
A whistling woman and a crowing hen are neither use to God nor men.
Wish in one hand and shit in the other and see which gets full first.
Daft as Arseholes.
He wouldn't know his dick from his thumb if it didn't have a nail on it.
You look like a sack of shit tied up with string.
You look like a bundle of arseholes tied up ugly.
Straight as dockey's hook.
Straight as a dog's hind leg.
The man who never made a mistake, never made anything.
The wind will change. Or if the wind changes you'll stick like that (to someone making faces)
Thick as two short planks.