HOW: Begin the exercise by getting yourself set up in good posture sitting upright looking straight ahead. Then place your hand or fingers on the back of your head and try to push your head and neck forward, however, use the muscles in your head/neck area to match the resistance. Don't let your head move.
FEEL: You should feel the muscles in your head/neck area, more so the back-side muscles working to resist any movement.
COMPENSATION: Do not lose position, don't let your head or neck move. If it does, push less so that you can match the resistance.