A panty liner is an absorbent pad worn in a woman’s underwear for feminine hygiene. Uses for panty liners include absorbing regular vaginal discharge, controlling menstrual flow, incontinence and tampon backup. Some women wear panty liners on a daily basis while others wear them only during their menstrual cycle. According to Lisa McGuinness and Chris Boral, authors of "Gotcha Covered," using panty liners is simple once you know how to secure them to your underwear correctly.

Lay your underwear out on a bed with the center patch facing upwards.

Peel the protective backing off the panty liner to expose the sticky surface. If the liner has wings, peel the protective backing from each wing as well.

Press the sticky surface of the panty liner onto the center patch of your underwear. If the liner has wings, fold these wings underneath the center patch of your underwear to secure it to your panties.

Put the underwear on with the panty liner facing toward your body.

Wear the lined panties for no more than eight hours before replacing the liner with a new one. Discard the old panty liners in a trash receptacle.