when one puts on a veteranary cone, shakes up a beer (preferably a yeungling) then proceeds to spray the said beer toward ones face and drink as much if the incoming beer as possible.
after jimmy was done shamrocking the beer justone gave him a hot carlson.
The double handed action of your local bar tender as they top off your Guiness with said 'Shamrock' motif.
'To Shamrock' ; verb. To ladel your lover in an artistic fashion with your 'man muck'.
Post 'Shamrock' a wet wipe (or other absorbant material) is required. Its is advised to steer clear of using the curtains or other handy soft furnishings as febreze and vanish are not up to the job in hand.
"Why my sweet, do we have time for a 'Shamrocking' before we go to your parents for sunday roast?"
when a man colors his penis green in rememorance of St. Patricks day and proceeds to have sex or recieve head from a woman. There will be green marker left behind on the woman for everyone to see.