Post-canon post-reunion post-reuinion-sex. Dean takes Cas out in the Impala for a drive for the first time since he got back a year after he was taken. Before Dean starts the engine he hesitates and gets a little shy and defensively says "don't laugh at me, okay? I need them." and he pulls a pair of plastic framed glasses out of his jacket front pocket and puts them on.
Cas does not stop staring at him, which Dean can only handle up to the first stop light. There's an heated blush on his face when he barks:
"Quit the surveillance Big Brother. Something wrong with my face?"
"It's a compliment. Your resourcefulness and resilience have allowed you to live past the time you were intended to by fate."
"You need to go back to charm school, Thermopolis. 'You've aged' is never a friggin compliment."
"It is. You've aged, and you're taking care of yourself."
There's a touch, light, to the side of Dean's face, tracing gently up under the gap of his glasses to caress his crows feet.
"Cas!" Dean complains, "I'm driving!" But he doesn't push his hand away.
"You're growing," Cas continues, sliding a long finger over Dean's eyebag, "You've lived." He taps the leg of Dean's glasses as he withdraws, adding, "You have defied God."
Dean tries very hard to follow the logic, feeling his face screw up as he does, but he's got nothing. "Huh?"
"Chuck's design for humans was faulty, amateur. There was much he did not account for. In creating the means to live, and live well, with the body you have been given, humanity has proven its superiority to God himself."
Dean scoffs, feeling a little shy again, "It's just glasses, Cas."
"The product of thousands of years of innovation. The work of thousands of people across millenia." Cas pauses for a moment, then asks, a touch breathless, "Can I tell you what I like to imagine?"
"I like to imagine, when I think of the work of other humans across all of time, that they were doing it all in service of you."
Considering this, Dean lets a Jeep turn onto the road in front of him. "Is it like a sex thing?"
"It's not a sex thing. It is the placement of my desire for you over the will of thousands. My love supercedes their true intentions, their ambitions, their circumstances. I am reappropriating their care to act as a vessel for the depth of my feelings for you."
"Hm. Sounds like a sex thing."
"Okay, tell me this, then," Dean says, turning to face Cas at the next red light, "Do you or do you not want me to wear the glasses next time I suck you off?"
"...yes, I do want that."
"I rest my case. And hey - just a tip, from one flirt to another. Next time you want to bring up your hot librarian fantasy, or whatever, don't start by calling the other person old."
"It's not a librarian fantasy, it's a you fantasy."
"Yeah, yeah. Not like I haven't got you-fantasies of my own. How about this: I'll wear just the glasses if you wear just the trench coat."
"I think I could be persuaded," Cas says, and he's smiling, and Dean's smiling, and when he catches a glimpse of his own smile-lines in the rear-view mirror magnified through his glasses, he thinks maybe he gets it. They made it. They're alive. There's proof of it.