Knuckleberry
The act of being a knucklehead and a dinglberry at the same time
When Jared broke up with his girlfriend after two years over a text message he was acting like a knuckleberry
Knuckleberry-Finn
Finger a girl who is menstruating until she climaxes on your hand.
She was on her period, but that didn't stop me from giving her a nice knuckleberry-finn. It took 20 minutes to wash my hands after wards.