He quickly covers your mouth as he leans out the door and talks to Kōyō while hiding you away.

Kōyō: "He's your ex partner in the mafia. Of course I'd be worried and check in on you. I don't trust Dazai."

They've been bickering like siblings for five minutes.

Chuuya: "Yes I know that he's my ex, but can't two people reconnect, I only see him as a friend."

Kōyō: "Chuuya, I'm just worried. I don't trust you with Dazai."

You know that's the biggest lie he's ever said. You had told the Agency you'd be going to bed, but you didn't say where. (In his sheets~).

His hand was still over your mouth as he leaned out of the doorway and had this conversation. Your back against the wall, his hand keeping you there and keeping you silent.