Start standing with one end of the towel under your right foot. Hold the other end of the towel with your right hand.

 Drop your right shoulder and hold the towel low enough so the towel is pulled taut.

 Seperate your feet a little wider than hip width apart.

 Slowly lower your left ear . . .

 to your left shoulder. Don't pull your shoulder to your ear.  

Hold for 10 seconds.
You should feel a good stretch down the side of your neck.