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1.
slang term for boner
I had a beef knuckle in the showers after football
by Brad Hull November 18, 2006
 
2.
When a girl has her pants pulled way up, and you can see the outline of her beef curtain.
Dylan: Did you hear that Hunter fucked Kassie?

Kody: Ewww, she has beef knuckles.
by DildoNelson April 12, 2010