Grab a band at the ends. One end in each hand. Extend your arms overhead and reach back behind you. Roll your should blades back and and bring the band behind your back and reach toward behind and back toward your butt. Then return back up to the top position and repeat. This exercise greatly increases shoulder flexibility and enhances your range of motion.
Resistance Band Shoulder Dislocations Exercise - Start Position
Resistance Band Shoulder Dislocations Exercise - Finish Position
Resistance Band Shoulder Dislocations - Rotator Cuff Exercise Video