Here’s a ficlet about Dean dragging Cas to the movies to see Pacific Rim because reasons. Set in Season 9 and grossly fluffy.
As soon as Cas is situated in the bunker, looking like himself after a long shower and a proper meal, he tells them everything. About the traveling, living in shitty motels and sometimes, with the homeless, about the angels pursuing him, everything. They go to bed at 4 am, exhausted from talking through most of the night, worried but glad to be together again.
But it’s not like they can pick up the next day and start hunting angels or something. They don’t even know if they should. They don’t know anything. So unless those sons of bitches come after them, they’re not about to go in blind. Cas, though, looks like he wants to, if not go after them, do something, because he’s almost thrumming with nervous energy. He can’t though, they know that much, not when he’s just fresh into humanity. So Dean and Sam try to direct that energy towards helping him transition into humanity, show him the ropes so to speak.
There’s only so much they can show him though, the guy learns pretty quickly and having been among humanity for so long, hell, having seen humanity develop, he knows the basics. And well, as the learning stops being interesting, he starts getting kind of mopey and really into the library. Spends hours holed in his room with a pile of books and only comes out with some coaxing from Dean when his stomach starts protesting. But when Dean sees him disappearing with a sandwich into that black hole of a room, he figures enough is enough and it’s time to initiate phase two of Humanity 101. Having a good time.