A dirty way of saying surprise butt-sex.
1.Waffles: Hey Dwarfo, I'm gonna cum to your house and knock knock on the back door. If you don't answer, I'm gonna bang bang!

Dwarfo: Yeep! I hope it isn't too surprise!

2. What rapists say to little kids when they are gonna butt-rape them.
by Dr. Dirty August 15, 2008
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Surprises or stuns
That dinner really knocked me back!
by smartguy55 November 13, 2021
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a) the act of specifically raping a virgin teen girl in the anus

b) arriving somewhere unexpectedly, when they least expect you.
sociologist of criminal behavior, (visiting the cemetery of Marion State Prison, Illinois): Ghost Poinsalet, I hear you are famous, even among ghosts, in this cemetery. What have you been incarcerated, and executed for, 27 years ago?

ghost of Matthew Poinsalet (character from Dead Man Walking): Sir, it was for knocking at your back door, definition b), to the house of 2 virgin teen girls, then committing knocking at your back door, definition a), and then finally murdering my victims.

sociologist (under his breath): How atrocious, may we condemn all child rapists and murderers to the electric chair, Amen.
by Sexydimma June 1, 2015
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