Define Knocking Boots Meaning

Knockin' boots is an old western term for having sex. Derived from both he and she stripping down and slipping their boots under the bed which sometimes made a "knocking" noise. Sometimes the boots are/were left on during sex and the boots would knock during all the action.

(v) To have sexual intercourse. The knock refers to the man's hips hitting the woman's ass, which produces a slapping sound. The motion literally knocks her boots (buttocks).

The act of knocking two boots together, usually leather, for cleaning purposes or to test the strength

hetero vaginal sex. The sound made sounds like knocking boots, unless one of the partners is fat

Clashing clogs, Bashing birkenstocks, lashing laces, hitting heels, etc.
There are many ways to say smashing shoes, but knocking boots is the most popular by far.

Also unrelated is the topic of fucking.

When you want to have sex with a girl very badly.