((Honestly, I only really ship this with your Crowley at this point, 'cause I love how sweet they are to each other, and how they're the only ones who truly understand each other. Like, Crowley isn't bad, and Cas isn't self-righteous or whatever, so they can relax and be themselves together. Cas doesn't have to always choose the right thing, and Crowley doesn't have to act like the all-mighty King who'd rip people's organs out and use them for garlands. And I like the fact that Cas knows what Crowley's doing when he's away, and Crowley knows what Cas is doing when he has to leave, but neither of them care because when they're together, that's all that matters.
I have a lot of trouble shipping Cas with other Crowleys, except maybe the cured ones, because a lot of other Crowleys play up his evil side and don't give room for any sort of softness or gentleness. So like, with other Crowleys, it's a constant fight for who's better or Crowley's dominating Cas completely, and I don't like that as much.))