One of the most creative ways I got away with smoking on stage, during a scene a charactor asks for a cigarette, since the actor didn't smoke and was hell bent on not smoking (even herbal), I used some cleaver stagging.  She asks for the cigarette, few lines before she receives it, then she does, she has no lighter, few lines later she receives lighter, then throughout the final lines she attempts to light the cigarette, but has lines everytime she goes to light it.  Never added lines or subtracted lines.  Kept with the script and it looked natural for her to old the cigarette and wait as she speaks never having a chance to light up before the black out.