to do something fucked up or wrong. Usually followed by someone waving a small black flag and the words "You done fucked up, son"
by DistructiveHamster September 15, 2013
Mark was chugging four locos when he got up and shoved Christian hard on the toilet.He was so black flagged.
by Myersgirl November 02, 2013
Behind Susie's back Wilkie formed the two-fingered x sign above her head - blackflagging her in no uncertain terms to Jimmy who had approached unsuspectingly with the intention of spading her.
by angela June 06, 2003