The visible outline of a girl's thong. Usually seen under her leggings. Many girls wear thongs to avoid panty lines, only to get thong lines instead. Slightly harder to notice compared to panty lines, but ultimately just as obvious. Most guys notice them, but say nothing. Instead they take pictures and upload them online. Just google "Thong Line."

when you've done something so cringe you can't stop replaying it in your head and it stops you from getting on with your every day life