Rose Petals
From my experience it is both a sensory and mental thing. In the sense that it has a nice gentle flavor and pleasing aroma, but also that it can provide a mild buzz similar to nicotine, and a slight feeling of euphoria. The actual effects may be more placebo than anything but either way it is a pleasant thing to smoke if you do not want to smoke weed or tobacco. Some people will mix rose petals in their weed or herbal cigarettes.