I tell people when they ask that it is a vaporizer and not a cig. I explain to them it's a battery and a heating element. I also tell them I have been vaping over a year and no longer use nicotine, I just like the hand to mouth experience that resembles smoking which are both true. I'll blow them a cloud if they how any interest and once they see how quickly it dissipates they usually either comment on the nice aroma or if they are a smoker or know of one that they would like to see quit ask questions on what to buy and how to get started which I always take he time to explain in detail.
I didn't read all the responses but did see the one about the one jerk everyone will run into. The best thing in the case IMO is to apologize and don't do it around them. No sense in arguing with someone close minded and uninformed, never seem to get anywhere that way. Again JMO, boB