Sam knows that being in a relationship with an angel is different. Especially an angel like Castiel. Most of their time is spent hunting or looking through old lore books. They're a very goal oriented couple, especially since their relationship started while they were trying to stop the Apocalypse. So he gets it, really.
But he misses it sometimes. The little things he used to have in other relationships, but mainly with Jess. The long nights studying together, the early morning breakfasts in a little diner off campus, the lunches they traded at each other's jobs. The hand holding, the forehead kisses, the hugs from behind. Movie nights, game nights, date nights. He misses all of that.
Don't get him wrong, he enjoys his relationship with Castiel. He knows it's unconditional love. For God's sake, Castiel stuck it out with him even when he was literally the Devil. But on his worst days, the days where it feels like all his mistakes are written on his face and he can't figure out why Dean stays with him let alone Castiel, he gets....sad.
It's one of those days and they're bunched up in a booth at some backwoods diner when he realizes his eyes keep slipping over to the two teenagers curled up around a similar table across the room. Their faces are about an inch apart, their hands twined on the table, and it's extremely sappy. It sends a sharp pain through his chest, but he ignores it as he tries to focus back in on the conversation.
“-and we'll be wrapped up by midnight,” Dean's saying, a little serious but mostly smug.
“Great,” Sam says dully. He pushes away from the table and stands with Dean and Castiel, ready to get this hunt over with so he can go hide in his bed for a week. Maybe then his head will be a bit clearer.
They go out and kill a werewolf and it's just as sad and bloody as it always is so Sam trudges into the shower with an air of hopelessness. He's tired and sad and sick of spending his nights covered in monster blood and then pretending like it's okay the next morning. He's just contemplating drowning himself, something he contemplates every one out of three showers, when he feels someone in the room with him.
The sudden warmth and electricity in the air lets him know it's Castiel, but he still doesn't relax. In all the years they've been doing this, they've never once shared a shower. A bed for three days after Sam finally got his soul back, but not a shower.
Hesitant hands are sliding around his waist, a chest pressing against his back, and Sam is just starting to wonder if he slipped into an alternate universe- who know what this bunker can do- when Castiel drops his head against his shoulder and sighs into his skin.
“I'm sorry, Sam.”
“I am continuously trying to understand humanity,” Castiel explains quietly, “Yet I continuously fail to apply that understanding to you.”
“I saw you. This morning. Watching those teenagers. I could feel how much you wanted that.”
Sam tries to blow it off, never wanting Castiel to feel like he's failing in their relationship. “They were embarrassing.”
“They were in love,” Castiel says. “We're in love, but we don't sit like that in public. Why?”
“It's not appropriate for grown men,” Sam says. He's thankful for whatever magic always keeps the water hot in the Bunker because he's starting to think they aren't going to get out of here anytime soon. “It bothers people.”
“Other people are not part of our relationship. Does it bother you?”
That pain from earlier comes back. “No.”
“You would like to sit like that,” Castiel concludes.
“Maybe not in public,” Sam jokes weakly.
“I understand,” Castiel says before laying a kiss on his neck, lips stiff. It's awkward but it fills Sam with affection because his misfit angel is trying so hard to give him what he needs. “I will let you shower now. Come join me in bed when you're ready.”
The next morning Sam sits reading the news on his laptop when Castiel brings him a cup of coffee and settles beside him, laying his head on Sam's shoulder. Sam can feel the heat blossom on his cheeks when he catches sight of Dean's raised eyebrow.
“Gross,” his big brother says, but the light in his eyes lets Sam know who gave Castiel a clue.
“Shut up, jerk,” Sam says softly, laying his head against Castiel's.
It's a good day.