That's a weird one, but that is kinda what fetishes are about.
I think it would be ok to talk about this with her, but not with the intent of having her do this, more as a matter of discussion, sharing something personal and coming closer together. So is keep the conversation light and don't put any expectations on her, never be manipulative.
She may also find subtle unconscious ways to incorporate aspects that mimic smoking in some ways - would seeing her suck a lollipop do anything for you, say the kind with the white paper stem? Or the way she holds a pen?
I think it would be ok to talk about this with her, but not with the intent of having her do this, more as a matter of discussion, sharing something personal and coming closer together. So is keep the conversation light and don't put any expectations on her, never be manipulative.
She may also find subtle unconscious ways to incorporate aspects that mimic smoking in some ways - would seeing her suck a lollipop do anything for you, say the kind with the white paper stem? Or the way she holds a pen?