if you dont like wasting that smoke, do what i do... use a penny or a nickel to cover the bowl. right befor you clear the bong (or before ur done hitting if it has no carb) cover the bowl and keep it covered to put it out...

after a while, you'll get to the point where you can cover the bowl the whole time. you can use it to get way better hits cuz it cuts off most of the air and you end up inhaling only smoke