The act of plugging one nostril with a finger and blowing out the other nostril in order to get rid of snot; typically done without a tissue.
Guy 1: Dude, I have snot in my nose, but there’s no tissues anywhere.
Guy 2: Don’t you know how to Canadian blow?
Guy 2: Don’t you know how to Canadian blow?
by Pseudanonym March 18, 2019