[Yamaguchi blinks and his smile fades a bit, with his cheeks tinged pink. He's not the best at reading people and has no idea of what Oikawa knows, leaving Yamaguchi to wonder uncertainly if he's interpreting the other man's reaction wrong.]

Eh? …Yeah, but, he's really more of a tutor, if you want to be specific! He used to have a job in civil service, so…he's been helping me through my courses on public law…