In your own time
Sounds like 'take your time'. Means 'hurry up'.
Grand so, in yer own time dere, de Mass is only after startin'.

Shall I translate it into posh English for you, head?
Do pull up a chair. Here it is in posh English.
Very well, proceed at your leisure. Mass has merely commenced.
Questions
What does in your own time mean in Ireland?
Sounds like 'take your time'. Means 'hurry up'.
How do you use in your own time in a sentence?
“Grand so, in yer own time dere, de Mass is only after startin'.”
Updated
On the list: Irish slang phrases