Seto has always done what's best for Anjou. He's learned to read her so when she's in playful mode he's in his normal reserved mode. When it's important Seto steps out and up to do what's necessary. Just like the slut comment, normal Seto wouldn't do something for himself but for Anjou he does.
But until he finds his calling he will always be unsure of himself with Anjou and therefore default to tradationlist Japanese manga MC relationship progress mode.
First, great drink
second saaaame. im Currently binge reading to caricature up so it was literally 5 minutes ago. I NEEEEEEEED TO KNOW WHAT HAPPENED WITH INUYAMA