Often used as an honest replacement for "lol," "lmao," or any other form of abbreviated laughter that's often insincere while maintaining their function as a tone indicator.
Person 1: "Hey, Person 2! Are you still coming to the library around noon?"
Person 2: "Nah, I don't read TIS"
the region between the genitals and the anus that used to have enough identity to be neither genitals nor anus (the 'taint) but has been sufficiently damaged to now become either genitals or anus