"You don't know your ass from a hole in the ground." Illustrate with a pen and paper drawing a circle and a cracked circle. Now ask which is your ass and which is the hole in the ground. Subject points to cracked circle and you mock while pointing to their real derriere.
If an individual wants to do bodily harm to another, he knows where to find the subject of the threat.
This phrase is commonly used in the African-Americancommunity.
Subject testifies in Court against a drug dealer. At the end of the testimony dealer sais: I know where you live! It means that his people know where to find the subject and exact their justice upon him.
the line that you say to someone you do not know or barely know in response to them calling you bro. They may think they are cool or are chill and call you a bro. However, by saying don't bro me if you do not know me, you are telling them that he is in fact not a bro and does not have the right to call you a bro. One must understand what a bro is in order to say the line.