If they’re feeling PMS symptoms or think their period might be about to start, they can wear a light underwear liner, pad or period underwear for “just-in-case” protection. It’s not a good idea to put a tampon in if they don’t have their period because that can cause an infection. If they’re not bleeding, or even if their flow is very light, then inserting and removing a tampon can also be uncomfortable. It’s better to use a liner, pad, or period underwear instead.