Carve a small stick that fits in your hand comfortably. It is a good idea to file down a rectangular block of wood, so you can attach a hinge to the bottom of the mouse. The hinge allows the user to shift his or her wrist angles. Stick the switch on a good spot of the stick where you can press it without getting in the way of writing. Stick the hinge to a uncluttered spot of the mouse base.