Knock The Back Out Of Edit Meaning

1.

This is normally associated with sexual intercourse carried out at a rough and vigorous pace (most commonly doggy-style), although it can be associated with any activity where it is performed with gusto. This means that you did whatever it was you were doing with particular enthusiasm and/or speed

Good morning Casper. I had a cracking time knocking the back out of Lady Clementine Smyth last night

or

Gadzooks, I could certainly knock the back out of a few glasses of Moet this evening

See zest, doggy-style, shagging, enthusiasm