A "smokers thumbs up" has the same meaning as the regular "thumbs up" but involves a nice twist. Instead of an erect thumb and clenched fist, the smokers way is either: act as if your holding a pipe with a finger over the carborator or rush, but all without the pipe, or act as if holding a lighter, just with out the lighter.

When you eat dirt for the first time and leave your family to build a shack in the woods