https://www.youtube.com/watch?v=IWDN-RW-at8
The "shoulder dislocate" exercise. Its an amazing mobility drill to loosen up the shoulder joint and muscles, while also strengthening and stabilizing them.
SaturnoMovement gives a thorough explanation of the movement, what to be aware of, what to do and what to avoid. SaturnoMovement is a good youtube channel source for all things mobility and calisthenics.
The video recommend to primarily using a stick, in my experience its better to use an elastic band in the beginning. Especially if you can't outward/externally rotate your arm (when the arm is down by your side) so that the palm of the hand faces more backward than outward to the side. The elastic band will make allowance for the movement where the stick would stop you dead in the movement.
