I don't know where to store this. I imagine if I ever had one, I'd keep it in a nightstand like a lot of people. It would probably occupy the same space as the other stuff used for those special occasions. I'd try to make sure that access was quite limited as well. I'd probably make sure to put it away in its safe place when done so it doesn't get in the wrong hands. Still, I am always surprised when I get questions about how to replace one. Or how quickly can it be replaced? Then I'm surprised that people think this is their only option. I can think of at least 8 other options, but that's just me. Seriously, how do people let these fall into the wrong hands?
Over the years I have heard:
My dog ate my diaphragm.
My kid chewed my diaphragm.
My son wore it as a yarmulke.
Okay. These examples likely mean you left it out. I'm sure the kids could riffle through your drawers but by the time you have kids, you should probably move the other stuff in that drawer as well.