Why do women put their necklace on their lip?

Women may place a necklace on their lip as a temporary way to hold it while adjusting or putting it on, especially if they're alone or don't have a mirror handy. This action can also be a playful or stylish way to showcase the necklace's design before wearing it. Additionally, some might do it for a quick photo opportunity or to draw attention to the accessory in a unique way.