Glad you asked...
Some people will usually place the hairspray up close to their nose and then spray the air spray then take a deep breath to breathe in the hairspray.
Then again, this answer might help you...
I suppose if you really want to inhale hairspray, you could spray it into a bag and then breathe in the contents of the bag. But, that's really dangerous and could land you in the hospital or the graveyard. Why would you want to do that?

