The reverse sweep is almost an exact opposite of the forward sweep.  It starts from the rear of the boat with a low brace rather than being angled in the water.  This provides you some extra stability when you start the stroke.  This time you sweep the paddle in an arc towards the front of the boat while turning your wrists to expose the non-power face of the paddle blade in the water.  As the paddle turns into the water, it propels the boat towards the side you are paddling on.  Leaning the boat on its side and turning with your torso makes this stroke much more effective.  The old adage "Turn with your Abs" is a good one to remember.  The forward and reverse sweeps can be combined to spin your boat much faster or even do donuts (360's).  We will practice spinning the boat in the class.  The following two films are the same as in the forward sweep article as both sweep maneuvers are typically taught together.

This is an excellent video on the sweep stroke from Werner Paddles: The Sweep Strokes.

This is another good example of the sweep strokes from Mike Aronoff at CKAPCO: The Sweep Strokes.