Tilt your head to one side and then to the other. Slowly tuck our chins and bring our head forward. Roll it around to the other shoulder. Stop, so that you do not hyper extend and go outside the parameters of a normal, cervical movement.
Grab the edge of the bench or whatever you are sitting on and then tilt your head in the opposite direction. Meet your ear to your shoulder. You should feel this stretch down into your arms, and sometimes even down into your fingertips.
Let your hands hang by your side. Lift your shoulders up, shrug, and let them come back to center.