I like the wildcard of this effect: just pucker your lips and blow, it comes out differently every time. Started with a 2 coat base of Sinful Colors Tokyo Pearl then dipped the tip of a straw in Essie After Sex and blew onto the nail.
There really isn’t much to worry about in the “how to” department — it’s a straw and you blow through it, the end. The quicker you burst the air out of the straw (or empty pen cartridge if you want a little more focused of a spray) the more streaky and splattery it gets… if you just sort of puff the blob of nail polish out you get more of a solid cover (see my ring finger).
Taping off your fingers is pretty critical for the mess it makes, but the end result is fascinating to stare at.