Like others have said, you should only be smoking if it's the right setting.

But, when I used to smoke (on a break, focusing on college), I did not want to smell like weed on the off-chance a cop happened to be at 7-11 or wherever, so I can understand where you're coming from. It's ridiculous what they can do with "probable cause".

If you're worried about smelling, use common sense. Go outside. Wear a coat, zip it up. If you're worried about your hair smelling, wear a hat. Blow the smoke up and away. When you're finished, take off the coat (or change your shirt if you prefer) and hat. Wash your hands. Chew some gum. Maybe a dash of cologne, not too much, or you're smell like that guy.

With that being said, some of my favorite memories of smoking have been totally clamming a tiny room with some friends to the point where smoke looked like Greek Gods (at the time :stoned and not giving a fuck about wreaking.