If you really want to stealth vape follow these instructions.
1. Get a drink cup from a fast food restaurant, some short pieces of elastic bands and some "bendy" straws the same diameter as a drip tip.
2. Place your PV into the cup with the button pressed up against the side.
3. Make a hole in the side of the cup just large enough for the button to be pressed.
4. Glue the elastic bands to the cup sides so that they can hold the PV in place. It also helps to then fill the cup with paper towels or other filler.
5. If your button lights up put a small piece of black tape over the hole to hide the light. Make sure you can still press the button.
6. Put the short end of the bendy straw into the tank/carto or whatever like an extra long drip tip.
7. Place the lid on the cup with the straw poking out.
I think how to use this should be pretty self explanatory. No one is going to question you sucking on a straw from a McDonalds cup. Just be careful about blowing the vapor and you are all good. If someone does see the vapor and glares at you, just remark to yourself: "Damn this drink is so cold I can see my breath."
Enjoy.