You are/were a sheep member.

After the sheep went through with their plan to kill Chuuya, which up to you you either had no part in it or helped, he made the deal with Dazai blah blah blah. When the PM soldiers came out to shoot and kill GSS they accidentally shot you in the back... twice... So according to their deal Chuuya was able to 'keep' you, and Mori had patched you up. You are sleeping with Chuuya, in a bed for the first time, completely unaware since you blacked out at the shots.