(idiomatic, vulgar) To have an adequate level of knowledge or skill; to understand what one is doing or talking about.

Synonym of know one's ass from a hole in the ground

Alternative form of it's an ill wind that blows nobody any good

What is useless to one person is valuable to another.

Alternative form of have one's head screwed on

present participle of get the dirty water off one's chest

Third-person singular simple present indicative form of get the dirty water off one's chest

(UK, idiomatic, slang) To get sexual satisfaction, especially after a period of abstinence.

simple past tense and past participle of get the dirty water off one's chest

Alternative form of in the land of the blind, the one-eyed man is king