I have a lot of smokers friends and they usually have the most interesting conversation that I do not want to missed when they smoking together.
As a non smoker, I never bring cigarette or lighter, but I do not want to be a passive smoker. Some says that passive smoker have the same risk compare to the active smokers. So if I want to join the conversation, I might as well smoking.
What I usually do, Just ask one cigerette to my friends and enjow the smoking sensation and a good conversation… Now consider your self doing a good thing. One, helping your friend the smoke less and two, its not your money you are burning… :)