Sometimes, you just want the essence of the spirit you’re using in a drink. If you’re just looking for the aromatics of a mixer or to keep a strong-tasting liqueur from overwhelming a drink, just a little goes a long way. Of course, you can just try to pour a 16th of an ounce of it in the glass, but that’s hard to do, especially if you’re on your second round of drinks and besides, it does nothing to show off your mad bartending skills.
Instead, try a wash – a method for getting a small amount of the spirit into the drink by washing the sides of the glass with it. Here’s a video on how to do it. I use method 2.