When i worked overnights i would just smack it at the counter, would reek but fuck it only drunk people occasionally came in that late anyways and plus my manager chiefs and we hang from time to time. If its risky tho or you think you could get caught id just wait, not worth losing your job over a buzz imo.
Aside from my current job, I used my vape pen at my old warehouse job all the time. I would just keep it in my shirt pocket and puff away when I had a break. Everyone thought it was "one of those new eciggs" so they never bothered me. It would smell a bit, but it was a big open ended warehouse, so the smoke could dissipate pretty quickly.
Not a bad idea, but I definitely wouldn't do that where I work now. I usually smoke beforehand, or have a small pipe in my pocket waiting for me afterwards, but never during. Actually I probably wouldn't do that anytime I'm on the clock. I enjoy having that bong rip after I get home from work and having it just knock me back into a couch for a few hours.