There are many ways to create contra-body movement. A previous drill worked on deliberately moving the shoulders in opposition to the feet in order to loosen up the center and improve the range of rotation for the torso. However, thinking about moving the shoulders while dancing tends to over-exaggerate the contra-body effect and looks awkward. The following drill is designed to create a more subtle contra-body effect, which looks better in west coast swing.
The Drill: Step forward with your right foot. As you step forward, think about holding back the right hip. This contrary motion (right foot forward, right hip held slightly back) should cause the right shoulder to pull back slightly. Then step forward with the left foot, while holding back the left hip. Again, a subtle contra-body effect should be produced as the left shoulder rotates back slightly. Continue walking forward while thinking about pulling back the forward hip.
The reason this method produces a more natural contra-body look is that the degree of rotation is controlled by the torso. If the focus is on moving the shoulder, it is very easy to disconnect the shoulder from the back, which results in an over-rotated look.