I've just been to an Irish pub today, and asked the landlord, what it meant ('Wack fol the daddy-o'), well he laughed and told me that I'll have to wait, til' I get older... since I'm only 17, he must've meant it was too "naughty" to tell me! ;)
So, know you know it IS worth finding out what it means! Or maybe he's just good a joking?! haha