Usually goes something like this.
Person: What the (pick an expletive) are you smoking?
Me: Its an electr- Its a nicotine vaporizer
Person: Oh, so is that one of those fake cigarettes from porn sites?
My Brain: Well no, I wouldn't call it that exactly, I mean its not really fake, nor a cigarette
Me: Er... yes
From here the conversation goes one of three ways
1. Oh, so can you put weed in it?
2. Person goes back to smoking their analog
3. Actual interest
In the case of the third option, I'm more than happy to go beyond my canned layman's explanation.
The only real exception to this in my experience was this one guy I talked to that said this, verbatim, "You know, you probably think those are good for you but they're not. And I know, I've had one before and then I had cigarette and I got all woozy. You get like ten times the nicotine. Its not good for you"
To which I replied, "Do you have any Science or anything to back that up?" and he told me that he didn't need it because of the aforementioned anecdotal evidence. I conceded with, "Meh, anything has gotta be better for you than smoking a cigarette." and he kind of just laughed and kept smoking and telling me how I was going to die ten times quicker... I never thought I'd see an anti-smoker with a cigarette hanging out of their mouth, but here we are.