Support xin isn't bad if you have good coordination because of his high base damage and early cc, plus his passive. It's just he'll get shat on if the enemy jungle is at all competent and camps out bot for a little until his lane gets a minor lead.
If this thread could stay on one topic for long enough it would be clear that he is talking about Thresh's W which is when he throws out his lantern. If the can't see the lantern then Thresh can set up some pretty nasty combos with the jungles. For example, you sit in bush and use W on yourself then Q the enemy pulling yourself to them and then the jungler clicks on the lantern for insta surprise butt decks.
In other news, NIGHT OF FIRE!
I will give you 10 IP if you can tell me the league reference.