What is Knock It Out?
1.
In the most basic of explanations, it means to cause a sex-induced coma. The goal is to fuck someone so well, that they fall to sleep and are late for work on a Monday when it's only Saturday.
MAN CALLING HIS GIRLFRIEND: "I hope you got another sick day, cause I'm about to knock it out."
GIRLFRIEND: "I'm on my way!" (doing 100mph)
See