When a person, including a girl, types "GTS" in a text message or social media chat, it almost universally stands for the phrase "Go To Sleep." It is commonly utilized late at night to signal that the sender is feeling tired, wrapping up their evening conversations, and logging off their device to head to bed. In alternative niche online contexts, it can occasionally mean "Google That Shit," depending on the playful or informal tone of the ongoing discussion between friends.