much like a dirty sanchez, it is when fecal matter is applied to the face in such a way it covers the entire lower jaw and upper lip. it is also typically applied by pirates (homosexual or not) to other sleeping pirates/crewmates/scurvy dogs as a joke. it is punishable by having to walk the plank, getting the shit beaaten out of you, or recieving a brownbeard in an act of revenge from the victim.
"yaaaarrrrr, captain, i gave steve a brownbeard last night! he has no idea!" this is followed by plankwalking and "aaaars" of disapproval, or a hearty round of pirate laughter.
As a man goes down on a woman she farts on his chin and gives him bad breath for the rest of the day. She then kicks him out and tells all of his friends that he has a small penis.
The foo got brown bearded. So none of her girlfriends would call him.
Last night I gave that chick from the club a mean brown beard. The weird thing is, she loved it!