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
friend 2: Were you “Getting behind the kneecaps” crazy?
friend 1: hell yea
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"