A can of compressed air that you inhale to get a very intense high. Used to blow dust off computers and other things. Gives a very numbing high and makes a cool sound in your head, along with speaking funny and the occational blackout.
Jimmy: Hey can you hand me that bottle of gas duster!
Frankie: Hold on, i'm about to get dusted.
Frankie: Waw Waw Waw Waw...Yooooooooo
Jimmy: Dude, you are dusted!