In Ireland, describing your lack of attraction to an unappealing person "I wouldn't ride him into battle"
Ride being slang for sex.
"An old broom knows all the dirty corners" - you can't hide secrets from someone who knows you long and well
When you're hungry - "I'd eat a nuns arse through the gates of a convent"
If someone has a cold - "Yer wan is a bucket of snot" "He's sicker than a plane to Lourdes"
Someone with a miserable expression - "Puss on her like a badly smacked arse" Puss means face
If someone asks you to do something you don't want to, or a nonsense question "Ask me Bollix" - not to be confused with bollox.
Gammy and Banjaxed are two of my favorite Dublin words - both mean broken.
Gobshite - describes someone who is a bit stupid and annoying, a very satisfying word to say.
Throwing shapes - dancing
Auld lad/auld wan - your father/mother
Feck! Not to be compared or confused with Fuck, it's a very gentle and inoffensive expletive used by all ages
I worked in Dublin for several years, Irish people talk a lot and very descriptively, swearing is creative and fluent and every day language is littered with the kind of expressions listed above. It takes a while to get used to but it's very, very, entertaining and uniquely eloquent.