Irish nightlife terminology that is used to describe the flirtatiousness of your drinking buddy or yourself. To be a 'flirty ahern' on a night out is to be 1. the singleton who had the most success in a group 2. significantly more flirtatious than your usual good self.
In any case, being a 'flirty ahern' is usually a good thing. It means you're striving to be the head honcho in the game of flirtatiousness.
Do you consider yourself to be a flirty ahern?
Scenario 1:
Friend to Flirty Ahern- "Flirty ahern came out last night did he? How'd you end up fairing with that one from the smoking area?"
Scenario 2:
Flirty Ahern to the gang at pre-drinks- "Gonna do a bit of a flirty aherne tonight"