The 2 on 0 react and support drill is a simple drill but it works on a habit that is often over looked, supporting the puck. This drill is ideal for a half-ice situation when you are splitting up the forwards and defense and working position specific drills.
Split up the players into 2 lines in each corner and place the pucks in one of the lines. The first player in each line starts the drill by skating inside the dots and then directly out towards the coach at center ice. One player will carry a puck and make a pass to the coach when they get to the top of the circles. When the coach gets the pass they fire the puck to one side. The players have to react to the loose puck. The strong side forward (the player that is on the same side as where the coach fired the puck) attacks the loose puck. The weak side forward follows and provides good support to the strong side forward. The key for this player is to not get too far ahead. They need to communicate with the puck carrier and stay below the puck and on the defensive side until the puck carrier passes or chips the puck to them. In a game situation the first player to this loose puck will most likely get challenged by an opposing player so you can add a passive defender or coach to make it seem more realistic.
As they enter the zone the puck carrier should go wide, get on their inside edges, and wait for the player that chipped the puck to get to the high slot. The player that chips the puck should get into the high slot as quickly as possible and call for a pass back from the puck carrier.