Oh, how those transmitter switches are a pain when they get loose! I looked all over the internet and only found a metal tool at banggood but they were sold out so I made my own.
This version comes in two version - one so you can grab the switch if it starts to turn on you when you tighten it. I made mine from PLA - won't outlast metal but then again it will cost you less the a nickel!
I suggest printing on it's side using supports between the object and the bed (but not inside).