If you're a pothead and live in an area where recreational marijuana has not been approved, you learn to become a master of the discrete hit. Or maybe not.
Some people in a restaurant happen to notice a dude acting suspiciously while sitting on a bench outside with his skateboard and headphones. He has pulled his black shirt over the top of his head and the people immediately recognize he's trying to cover up something.
Dude is just trying to take a hit from a glass pipe but it doesn't go too smoothly. His shirt catches on fire and it takes the dude a few seconds to realize it.
After a few puffs of air from his mouth have no effect on the flame, dude makes sure to finish the hit before standing up to remove the shirt.
Way to be discrete dude.