A trick I use is:
Create a Control Panel with a button that takes you to the next SceneMove the cursor over that button.Put tape over the optical sensor of a wireless mouse (now the cursor cannot move off of that button).Put the mouse in your pocket, on the floor, or take it apart and make a glove that completes the left-click circuit when you put your forefinger and thumb together.Now you can slap your pocket, step on the mouse, or close your fingers (with the glove idea) to trigger things.Further advice:
Use a USB instead of a Bluetooth mouseUse a USB-over-cat5/6 extender to put the usb receiver for the mouse above the center of the stage (for larger stages) or just closer to the stage (if your computer is already backstage and the stage is small enough for it not to matter).TEST TEST TEST! Always bench test your setup as much as possible, then test more once you're in the actual venue.