Most wasteful I've seen was called a "Milkshake" and I'm not talking about bhang.
The "bartender" starts by taking a hit off a joint but doesn't inhale it into their lungs. Instead they slowly blow the smoke through a straw into the bottom of a glass and then removes the straw. If it's done right and the air in the room is still then the smoke stays in the glass. The glass is slowly passed to someone who then "drinks" the smoke. I've only known one person who did this and she was quite insane and thought that her ability to be "bartender" made her special. IS there another name for this ridiculous process?

Hookah is 2nd most wasteful imo