snatch a knot 

To hit someone, usually used in a threat of punishment or retribution. A knot is generally snatched in one's ass, though variants include the neck and the head.

"Boy, if I ever catch you looking around under my mattress again, I'm'a snatch a knot in your ass!"

snatch a knot by Professor Darkheart September 11, 2005

snatch a knot 

a phase used to describe dominant male canine mounting behavior, as opposed to mating with a female . The "knot" refers to the dog's erect penis, which is "snatched" painfully from the other dog's rectum when the mounted dog submits. This phrase is used as both an insult and a threat to violently put someone in their place.

Someone should snatch a knot in his/her ass.

snatch a knot by Ms Semantics August 6, 2017