It's not smoking that's sexy, it's how you smoke. I see plenty I see outside of pubs and clubs smoking, holding a cigarette like it's going to explode in their hand, like it just doesn't belong there. With the lack of smoking in films and TV people have forgotten how to look good smoking. I'm not condoning smoking, I'm just saying it can look good done right. To be honest though, outside of movies, smoking very rarely looks sexy - people don't generally have enough class.
As for vaping? Can it look cool or sexy? I'm not sure. I think vaping is more analogous to pipe smoking than cigarette smoking, it's more of a hobby than a habit. It'll never be 'sexy' in the way cigarette smoking is, there's no rebelliousness or danger. But just as pipe smoking back in the 20's or 30's was considered pretty sophisticated, then vaping can find its niche as well.
Sorry, still trying to get used to the terminology!
