Take a belt or a chain and pass it around your body from one hand to another. Go higher and lower and than work to pass what you chose over the shoulder to the other hand in an X first going from up to down which is easy as you can dangle the object and find it with the other hand and than find a way to do it from the back and up over the shoulder. Find your way.

* the hand goes up and over the shoulder and the other hand goes around and up the back (like scratching yourself) to meet it.