>>714921936 (OP)Protip: Don't repeatedly press the button. Hold your finger stiffly against it and come as close as you can to depressing it without fully pressing it, then vibrate your entire arm. If you can vibrate your whole body then do that too, and it take some of the pressure off of your arm. You will never experience fatigue in your hands or fingers.
The fastest button presser in the world (Takahashi Meijin, 16 times in 1 second) uses this method.
https://www.youtube.com/watch?v=oJ4lmAFB7d4