Dean saying things to Cas he doesn’t realise are the angelic equivalent of “I love you”;
*Dean working on the impala, Cas sitting closely and watching*
Cas: How did you learn to fix engines?
Dean: Oh, my dad taught be the basics but it was Bobby who really showed me the ropes. It’s easy once you get the hang of it. Hey, you wanna try?
Dean: Well she’s due some fresh tyres. I could show you how to change ‘em?
Cas: *blushing madly* You- you want to teach me a skill of your lineage?
Dean: …weird fucking way of putting it, but yeah pretty much.
*Dean and Cas outside a bar at 2am leaning on the impala, Dean a little tipsy*
Dean: hey look! You can see the stars out here!
Cas: Oh, yes, they’re one of my favourite angelic creations.
Dean: You know when you properly ‘died’ for the first time I saw the North Star that night and named it Cas then when I missed you I could go out and pray to the star as if you were listening.
Cas: Dean, are you saying you- Dean did you worship me as a false idol?!
Dean: Huh, yeah technically I guess I did.
*Sam Dean and almost human Cas having a movie night, Dean making them watch Dogma to critique the angel lore*
Sam: Okay, I’m turning in.
Cas: The film isn’t over for another twenty seven minutes Sam.
Sam: Don’t care, too tired.
Dean: Cas it’s okay, let him leave. Although you look tired too buddy, you wanna call it?
Cas: I’m fine. I want to see the end of the story, if I am asleep at the end you may wake me and tell me to move.
Dean: Or maybe I’ll just be the one watching over you for once.
Cas: Why would you do that? I am not your charge Dean, it is not your responsibility to-
Dean: Dude I wasn’t saying that out of responsibility, I’m happy to make sure you’re safe just whenever.
Cas: *teary eyed* You… are offering me safe rest, freely and without expectation??
Dean: *so confused* Yup, again gotta work on your phrasing but still. Yes.
Dean: *stunned but secretly overjoyed* Not the way I thought that would happen but alright then. I love you Cas.
*he kisses Cas until they’re both to tired to continue. The second they wake up in each others arms the next morning they continue. Sam almost kills himself when he walks in on them naked together cuddling*