The literal meaning of this Irish term is "Guardians of the Chicks" (or "chickens") and is used in Ireland to refer to the national police force Garda Síochána na hÉireann or the "Guardians of the Peace of Ireland". The term is somewhat pejorative and is used disparagingly if jokingly.
When we had the bomb scare the Garda Sicíní was everywherestanding around uselessly talking about Sunday's match at Croke Park.
The Dirty Gandalf is the art of masturbating on to the Chin of your partner, creating a messy white beard of spooge, they must then shout "You shall not pass!". To add extra credibility to the act, midgets dressed as Hobbits may be used as well as other props like robes, staff etc. Photographs must me taken for posterity.
Darling , I have ordered midgets for tonight, get your robe on, its time for Dirty Gandalf to arrive.