What is Brown Knuckle?
1.
Shit on your hand or knuckle when wiping one's ass.
While wiping I got a case of the brown knuckle.
My roommate had brown knuckle on his finger.
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2.
When some one wipes their 
Tom had to use extra soap to get off the brown knuckle.
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3.
To fist another's ass.
Heather bent over amber, made a fist and gave her a brown knuckle.
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