How long have you been smoking? If it's been 1-2 months or less it should be easy. Past that, it's a little trickier.
Best thing might be to wait until you have a cold/flu. Personally when I'm sick, just thinking about smoking makes me feel worse, so I stay away from cigarettes. Since the first few days of quitting are the worst, and colds tend to last about that long, it would be a good way to get over the worst of it since you'd already feel like crap anyway.
And yes, I think it is a form of stimming. I smoke the most when I'm sitting at my computer, writing programs. It's something to keep me occupied when I need to take a little break, basically. When I'm doing stuff outside with friends (especially if they're non-smokers), I can go a 1-2 days without even thinking about it.