Sometimes he doesn’t even say a complete instruction just utters words like bum, bum, bum, or snaps his fingers.  Because derrick doesn’t have a piano, playing the songs, he has slum behind the dj booth, in front of a laptop and can stop and play the songs at intervals, while knowing the exacts second and minute where he can go back and play important song sequences.  Some of the dancers to bend over in lounges and relax their back muscles.