The exercise can help you achieve better use of your shoulder by improving its range of motion.
To Start: Find an open wall or door jam.
Facing the wall slowly walk your fingers up the wall. You walk up as far as you can while maintaining the space between your shoulder and your ear. This may decrease how much range of motion you achieve initially but it will your mechanics correct and decrease the chance of developing compensations.
Once you have the reached your maximal height, hold for 3-5 seconds and then slowly walk your fingers back down. Repeat this for 10 repetitions.