Quick answer

DUO Over & Under Glue Liner, Black is a 2-in-1 pen: sweep it along your lash line like classic liner, or apply it underneath for an undetectable lash bond. Decide which way you're wearing it before you start, because the placement, the wait time, and the pressure you use are different. If you want both a wing and lashes, draw the liner first and add the lash bond second.

Pick your method before the pen touches your eye

The pen does two jobs, but they don't follow the same sequence. As liner, it sits on top of the lash line and is judged by how crisp the edge looks. As lash glue, it goes underneath the natural lashes and is judged by whether anyone can see where the bond starts. Choosing first stops you from drawing a wing and then trying to glue a lash strip on top of wet liner, which is the fastest route to a smeared line and a lash that slides.

Method one: wear it as eyeliner

Work on a clean, dry eye with no leftover cream or oil on the lid, since slip is the main reason a wing loses its point. Start at the outer corner, place the tip where you want the wing to end, and pull the line inward toward the middle of the lash line in short strokes rather than one long drag. Build the thickness in thin layers instead of pressing harder; a pen tip that is pushed into the lid tends to skip and deposit uneven color.

  • Keep the elbow of your drawing hand resting on a surface so the tip stays steady.
  • If you wear lashes too, finish the liner and let it set before adding any lash bond.

Method two: wear it as an under-lash bond

For this method the pen replaces a tube of glue, so the line goes under the natural lashes rather than across the lid. Apply a thin stroke along the underside of the lash line, wait a few seconds for it to turn tacky, then seat the lash band or clusters onto that tacky line and press gently along the whole strip. Because the bond sits underneath, the lash base reads as your own lash line instead of a visible band.

  • Thin beats thick: a heavy stroke stays wet longer and shows through the lash base.
  • Press from the middle outward so the corners don't lift while you work.

What to pair with the pen

The pen covers liner and bond, but it doesn't cover every lash style. If you want weightless, barely-there volume, a soft underlash cluster sits naturally on an under-lash bond. If you prefer a classic strip, a nourishing adhesive is a better match for sensitive eyes or contact lens wearers, and it can be used on its own without the liner step. Matching the lash to the method matters more than matching the lash to the trend.

When the pen is the wrong tool for the job

A liner-glue hybrid is built for control and a clean finish, not for maximum hold under heavy weight. If you're wearing a dense, heavy strip, expect a thicker lash band to need more support than a fine pen stroke can give. And if your eyes water easily, test any new bond along a small section of the lash line first, since a product that performs well on dry eyes can behave differently on watery ones. The catalog for this pen lists a title option only, so check the shade name on the product page before ordering if black isn't what you want.

Two-way application, step by step

  1. 1. Prep a clean, dry eye: Remove oil, cream, and leftover makeup from the lid and lash line, then let the skin dry fully before you draw or bond anything. Checkpoint: if the lid feels slick, the pen will skip and the bond will slide.
  2. 2. Choose liner or under-lash bond: Decide before you start: liner goes on top of the lash line for a visible wing, while the bond goes underneath for an undetectable hold. Common mistake: starting a wing and then trying to bond lashes over wet liner.
  3. 3. Draw the liner wing from the outer corner inward: Place the tip at the outer corner where the wing should end, then pull short strokes inward and build thickness in thin layers. Common mistake: pressing harder for more color, which makes the tip skip.
  4. 4. Or lay a thin bond line under the lashes: Stroke the pen along the underside of the natural lash line, wait a few seconds until it turns tacky, then seat the lash base onto it. Checkpoint: a thin tacky line holds better than a thick wet one.
  5. 5. Press the lash from the middle outward: Work outward toward each corner with light pressure so the band or clusters sit flat against the bond line. Common mistake: pressing only the center, which leaves corners lifting within the hour.
  6. 6. Let everything set before you touch it: Give the liner or bond a moment to settle, then check in a mirror with your eyes open, not just closed. Next step: if the hold feels weak on a heavy strip, switch to a dedicated adhesive for that lash.

Product facts

  • DUO Over & Under Glue Liner, Black: DUO Over & Under Glue Liner, Black is a 2-in-1 liner and lash glue pen that can be swept along the lash line like classic liner or applied underneath for an undetectable bond. One pen covers both methods, so you don't need a separate liner and lash adhesive for a natural or winged look.
  • Seamless Underlash Extensions Refill, Naked: Seamless Underlash Extensions Refill, Naked, is a weightless, delicately curled, crisscrossed cluster refill designed to blend in and add subtle volume and length. These clusters suit the under-lash method because a light, seamless base sits cleanly on a thin bond line.
  • DUO Rosewater & Biotin Striplash Adhesive, Dark: DUO Rosewater & Biotin Striplash Adhesive, Dark, is formulated with rosewater and biotin and is described as suitable for lash users with extra sensitive eyes and skin, including contact lens users. If a pen bond feels too firm or your eyes are reactive, this is the alternative adhesive to reach for instead.