Fishtail eyeliner, also known as double-winged eyeliner, is likely taking over your Instagram feed. Lily Keys, a celebrity makeup artist, says, “It's a take on the retro [1960s] Twiggy eye. It opens your eyes and makes them appear bigger and more feminine, almost doll-like." This is how to achieve the look and have fun with it.
Double-winged eyeliner can lift and elongate your eye shape, since the extra winged line extending from the bottom lash line creates the illusion of wider eyes. To keep a steady hand, place your elbow on a table, then draw one line across your top lash line and one on your bottom lash line; then add the wings using mini-stroke motions.
For beginners, MAC makeup artist Keri Blair recommends using an angled eyeliner brush and a black eyeshadow to map out the shapes first, then go in with gel or liquid. Once you master the basic look, try experimenting with bright-colored eyeliners, or highlight the negative space between the double wings using a lighter color in the gap.