bowie knuckle 

Much like the movie, The Labyrinth, a "bowie knuckle" is an apple-sized lump in the male anatomy protruding in the groinal region. Particularly emphasised by tight spandex pants, or jeans. See also pud.

Girl: That guy had the hugest Bowie Knuckle I've ever seen!

bowie knuckle by Matthew Marvin July 22, 2007

Knucklebob 

Fingering your bootyhole or the bootyhole of another with your middle finger up to the third knuckle.

Beth was squirming last night when I did a little knucklebob.

I can’t shit today. I knucklebobbed myself last night.

Knucklebob by Eaton Holgoode October 6, 2017

knucklebone 

Another word for fisting

Jeff: Maria has let every guy in our grade knucklebone her

George: What a slut

knucklebone by LeManssssssss3 October 15, 2014

Knucklebomb 

Anal Fisting

Sebastian could really feel Tristan's fist in his ass. As he came, he thought this was the best knucklebomb he ever had.

Knucklebomb by Fnspidey August 31, 2017

Knuckleboarding 

A term for the action of accidentally dragging your knuckles across the top of the toilet water after leaving a poop.

The bathroom had a small toilet in it so when I went to wipe I made a few waves while I was knuckleboarding.

Knuckleboarding by Lyrlyrplnts4hire February 21, 2019