Ask your lack
A Waterford all purpose retort. Bring your girlfriend into it, whatever the row is about.
Heard in Waterford
Ask your lack.

Shall I translate it into posh English for you, scoby?
Welcome, welcome! Here it is in posh English.
Do refer the matter to your lady companion.
Questions
What does ask your lack mean in Ireland?
A Waterford all purpose retort. Bring your girlfriend into it, whatever the row is about.
Where in Ireland do people say ask your lack?
People say ask your lack in Waterford.
How do you use ask your lack in a sentence?
“Ask your lack.”
Updated
On the list: Irish slang phrases