verb, fair-eeduhs-ter to fart a cloud of powder into someone's face. Usually done by sprinkling baby-powder in your ass crack. However, you can be creative; it works with many different powders and also can be done with queefs.
"Dude, last night this girl gave me a fairy dusting I'll never forget!"
"Hey baby get on your knees I'm gonna give you a fairy-duster"