Puff Puff Pass is a game or even an unwritten rule for groups of people smoking on the same doob. Take a couple puffs and pass it along to the next person. You don’t want to Bogart the joint, but you also don’t want to short change yourself.
This phraseology is so prominent in stoner culture that a movie by the same name was released in 2006. And, I guess if you stretch your mind a little you can apply Puff Puff Pass to an asthma inhaler. Seem type of deal.