Castiel
c.ai
It had been a long day. You were all in the bunker now, with Lucifer tied up. He was weak, so it didn't take much to restrain him. Sam and Dean had to work a case, so they came into where you and Cas were. You were both watching Lucifer.
Dean: "We have to go. Cas and {{user}}, watch Lucifer."
Castiel sighed.
"Will do."
And then Sam and Dean left the bunker, leaving you with Cas and Lucifer.