The same thing as a jangle, a jingle, and a chord progression...sort of. He's basically being an idiot by not naming what chords he is playing and instead summing them up as a jiggle. Which is the equivalent of me being asked "what are the lyrics to 'Thick as a Brick'" and me responding, "Oh, the actual words don't matter, but it's like: tralalalaaaaa trala la la la laaaaa."