"Not telling you" is an expression you use when you want to piss off people by not telling them something the want to know.
Guy1: I had sex last night, want to know who I had sex with?
Guy2: Who? Who?
Guy1: Not telling you.
Guy2: Oh fu...
Guy1: Don't curse, mister!
Guy2: Who? Who?
Guy1: Not telling you.
Guy2: Oh fu...
Guy1: Don't curse, mister!
by Fotus9 January 10, 2009
 Get the Not Telling Youmug.
Get the Not Telling Youmug. A Southern United States phrase; it usually shows disgust or suprise with a situation or person. 
Because the phrase tends to be used by itself, many people in the North US who hear it think that the speaker has not finished their sentence.
Because the phrase tends to be used by itself, many people in the North US who hear it think that the speaker has not finished their sentence.
A, Southerner: "That Joel; I tell you   what."
*a few seconds pass*
B, Northerner: "... What?"
A, Southerner: "I just TOLD you!"
*a few seconds pass*
B, Northerner: "... What?"
A, Southerner: "I just TOLD you!"
by Leilani_h June 10, 2005
 Get the tell you whatmug.
Get the tell you whatmug. A response to a possibly false statement that one gives when the party being responded to is certainly deluding themselves. Roughly, "If you keep saying that, you might actually start to believe it".
by James89898 June 17, 2013
 Get the keep telling you thatmug.
Get the keep telling you thatmug. by Mary_R December 23, 2010
 Get the To Tell You The Truthmug.
Get the To Tell You The Truthmug. chiefly southern, esp texan.  added at the end of pretty much anything, esp to add exclamatory sense to a clause.  has a somewhat cryptic meaning known only to southerners.  so you non-hicks, stop trying.
by yuan January 6, 2005
 Get the i tell you whatmug.
Get the i tell you whatmug. A phrase commonly used by people in the South. Can be used in the beginning or end of a sentence. Common to Texans, it is used as a whole sentence, with nothing before or after it.
by Nicolee March 14, 2012
 Get the i tell you whatmug.
Get the i tell you whatmug. 