Black Flag had already created the platonic ideal of hardcore with their first three albums, but with Slip It In they proved that no labels could contain them. The title track and "Black Coffee" really get the mosh pit going, with guitarist and chief songwriter Greg Ginn adding new elements of sludge metal and jazz into the high-speed maelstrom. "My Ghetto" attacks from unexpected angles, while the instrumental "Obliteration" slows things way down, letting Ginn’s sinister riffs crawl all over his victims.