Kys can mean "Keep you safe"
Exemple: Team keep your safe! Team kys!
'Mate that's a sick polo you got there bro'
'Do you see any buttons? It's not a polo, KYS'
man 1: kys
man 2: what?!
man 1: keep yourself safe
man 2: oh kys too
Keep yourself safe
Means when you love your friends and want to show them you really care
You hsve a lovely opinion so i want you to kys