bust a sag
v. phr.— «“Bustin’ a sag” is what some kids call it when they let their oversized pants hang below the waistline to expose their underwear, and city leaders want to know whether they can outlaw that.» —“Council ponders saggin’ issue” by Tim Chitwood Ledger-Enquirer (Columbus, Georgia) Aug. 14, 2007. (source: Double-Tongued Dictionary)