Have you ever thought about it?
"The person smoking a cigarette reaches for the pack, takes out the cigarette, lights it, inhales, and then releases the smoke.
The person having sex reaches for her partner, unbuttons his shirt, fondles and kisses him, and you can figure out the rest."
Taken from the book: Body Language For Dummies
Honestly I never did until I read it!!
It is going to be interesting watching people smoke...and supressing a smile...