Place folded towel on weight plate(s). Lie supine on bench, head extending off of end of bench. Place plates on forehead with towel placed in between for comfort.
Move head up by flexing neck until chin touches upper chest. Return by hyperextending neck and repeat.
Balance weight on back of head with both hands throughout movement. Weight plate(s) can be tilted slightly to higher point on head to keep resistance slightly more consistent throughout movement. Tilt weight forward slightly at bottom and back slightly at top. Also see Weighted Neck Flexion positioning body perpendicular on bench.