Originally started in Dublin, Ireland. The act of inserting greased small potatoes in your girlfriend's ass and then packing them deeper through means of anal sex. To enhance the pleasure most people perform a Dirty O'brien while drinking a Corona light or Guinness.
While incarcerated Jimmy Boy O'doul enjoyed a Dirty Obrien at the hands of officer Paddy McFudge.
by Reed January 6, 2005
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