Doing a line

v.

Heard in Waterford, Clare and Kilkenny

To be going out romantically with someone. Usually 'doing a line with someone'.

In use

You'll have no luck with her, she's doing a line with a fella from Kill.

Posh English

You will have no luck with her. She is conducting a discreet romantic liaison with a gentleman from Kill.

Same phrase, other counties