Draw strokes are used to move your boat sideways.  They are commonly used in calm water for docking next to a boat or on shore.  They can also be used for quick side-slipping by an obstacle in a rapid.  Stern draw strokes are very useful when surfing waves.  Used in this manner, you are pulling the back of the boat sideways without pushing the boat forward.  When performing any draw stroke, always remember the paddlers box - never let the paddle shaft leave your eyesight.  These strokes require you to twist your torso and reach out a bit.

This video concentrates on the stern draw mechanics: Stern Draw.