Knackin 

To have explict sex, hard ,fast.

"come on love lets get crackin with the knackin"

Knackin by j.dougall November 19, 2003

I hear you knocking 

I hear you knocking, but you can't come in! A Fats Domino song about his feelings for a ex who wants to return!

I hear you knocking, but you can't come in! Go back where you been.

I hear you knocking by I, Wreckerrr November 13, 2020

Knocking

Something your family can’t do before they enter your room

*mother barges in bedroom whilst you’re in the middle of having sex*
You:”Holy shit mum, every heard of knocking”

Knocking by elv14 October 27, 2020

Knocking

Punching a Door until it opens

* Invention of Knocking *:

"I'LL PUNCH YOUR DOOR UNTIL YOU OPEN!"
Person: * Opens * Greetings!

Knocking by 7Macros February 21, 2021

If this van's a-rockin', don't come a-knockin'! 

A popular phrase and bumper sticker from 1970s. It means that people are having sex in the van if it's rocking and they don't want you to come in.

Bumper Sticker: If this van's a-rockin', don't come a-knockin'!
Van: *rocks back and forth*
Steve: I guess I shouldn't be knockin'.

If this van's a-rockin', don't come a-knockin'! by Dumb_Bass September 26, 2020

Ninja Knocking 

A favorite pastime of Urban and Suburban children.

The child will knock on an unsuspecting victim's door, but before the victim has time to answer, the "knocker" will dissapear in similar fasion to a ninja.

Tyrese: Yo brotha, let's go ninja knocking.
Tyrone: Wurd up dawg, ima say we get the ol' bitch down the alley.
Tyrese: Hellz ya mother fool

Ninja Knocking by joejoebuffalo October 7, 2009

Knocking

Something that occurs when combustion of some of the air/fuel mixture in the cylinder does not result from propagation of the flame front ignited by the spark plug, but one or more pockets of air/fuel mixture explode outside the envelope of the normal combustion front.

Modern cars are prone to low-speed knocking

Knocking by Sir. B October 24, 2020