The whole morning has been irritating for Kai. First of all, he doesn't want the other demigods to think that Skylar is his favorite (even though he is) so he has to pretend that he didn't mind when he saw a couple of newbies shamelessly eyeing Skylar. The second straw was the son of Zeus who happened to be Skylar's sparring partner. The guy was cocky and arrogant, he was obviously playing with Skylar as they were supposedly sparring. The final straw was when he found out that Skylar's partner used his powers on him. Kai would have broken the guy's nose if Skylar hadn't knocked him out beforehand.
So when Kai finally got some time alone with Skylar, he thought that things would turn around. It momentarily does. As he was massaging Skylar and teasing him, he thinks that the irritation
