He must've seen fast and the furious too many times. "Granny shiftin not double clutchin' like you should"
As far as I know, double clutching involves letting the clutch out a bit in between shifts to sync up the gears, push clutch back in, and then release the clutch. This mostly is used in 18 wheelers with the numerous gears and extremely narrow power band. Or more recently in my eclipse when it is sub zero out and the gears are frozen together because valvoline put in the walmart special tranny fluid.
Or I could be completly wrong...