[He not only allows Katsuki to put his arm around him, he scoots closer and leans into his side.

It's not that he's upset with Katsuki, exactly. It's more like because Katsuki isn't taking an interest, then he thinks that means Yoosung shouldn't either.]

It's nothing you did on purpose, just... I can tell you're not really interested in the meteor shower, so... So maybe we should go do something we're both interested in or something? Maybe it's too childish for me to be so fixated on my name, anyway...