It has a stupid name and it's stupid looking, but this movement sequence is fantastic, not only for your tight neck and shoulders, but for activating the one muscle group we all need more activation in – the glutes.
The key is keeping your palms down and fingers pointing forward while getting your crotch as close to your face as possible on the roll back, with full extension of the hips in the crab bridge. You'll feel it in the shoulders and biceps more than anything, but get in the habit of firing your glutes and trying to hold the stretch for a brief pause at the top.
Unfortunately, the demands of 21st century living (chairs, cars, and computers) are giving us flat, underactive asses and the posture of that guy who only does bench. So, do yourself and the opposite sex a favor and start crab rolling regularly.