Supine Band Pull Aparts
1) Start flat on your back with your knees bent.
2) Raise your arms up above your chest a little wider than your shoulders while holding a band
(Your setup should be similar to a bench press)
3) With your arms straight over your chest, turn your elbow crease forward to lock your shoulder blades closer to your spine.
4) Next pull the band apart straight across your chest keeping that elbow crease forward.
You should not feel any tension in your neck, so use a band that is a good resistance, but not too heavy that you are straining.