As itself:
Apply it from the middle of the upper/lower lip and even it out. Apply multiple times until the lips color you want to be.
As a lip base:
Apply a thin layer of Melty Lip Serum from the middle of the upper/lower lip and even it out. Then apply any lipstick on top.
As a lip gloss:
After using any lipstick, gently apply Melty Lip Serum from the middle of the upper/lower lip and even it out. (TIP: gently apply to not remove lip color by the Melty Lip Serum applier chip)