My dogs never reacted one way or the other. No reaction to my e-cig either....
BUT - I have a 3lb Yorkie that climbed into my lap while I was vaping and licked the LED tip as I was taking a drag

It scared me! I didn't realize what she was doing... and she licked it...
It made me hyper-aware of how dangerous and careless it would be if I left anything around! Some of the e-liquids smell good and she has since climbed in my lap and put her front paws on my chest as if she was going to do it again...
I'm aware of it now and all it took was correcting her twice. Now she'll climb in my lap, but just look up at me and not try to lick it.
Needless to say - I keep everything in a dog-proof box and I make sure I don't leave any paper towels, tissues or used cart filler on my desk or table. I throw everything away as soon as I'm done and keep my bottle caps screwed tight.