kys means kill yourself
take this an as example.
you are trash talking your friend and he says shut up you can say:
bro go kys (kill yourself) it will gravely hurt his feelings
man 1: kys
man 2: what?!
man 1: keep yourself safe
man 2: oh kys too
someone is asking for kinky yummy sex
hey anybody wanna have some kys? lol