Getting Kneecap 

The act of pressing ones knee on the underside of a man's testicles, then pressing the other knee on top of a man's penis. One will proceed to create friction until the man ejaculates on the thighs of the person giving kneecap

"Yo dude, Im dating this girl but she doesn't want to be penetrated until marriage, but I swear to God I am definitely getting Kneecap"

Getting Kneecap by TheRealTerryJerry February 18, 2023

Getting behind the kneecaps 

Having sex / most likely doggy style

friend 1: man i brought this girl over last night it got crazy “
friend 2: Were you “Getting behind the kneecaps” crazy?

friend 1: hell yea

Getting behind the kneecaps by Papa_stem82 April 28, 2021