Sam Winchester is arguably the best boyfriend in the world. One time he went to another city for a hunt and brought back the blueberry cheesecakes that Castiel has ever eaten.
He gives Cas breakfast in bed whenever he is upset over the death of his favorite characters. He'd paint Cas's nails to distract him from scary angel business. Sam's lockscreen is angel wings with the words Thursday in it, since Castiel is the angel of Thursdays.
It was obvious that they would legit never fight. And they haven't, not once. Until now.
It started with a silly game of Truth or dare on a drunken night. Since Castiel can't get drunk, the game isn't much fun normally. But the geeky bastard that Sam is, he convinced Rowena to make an Angel-worthy solution that would have the same effect on Castiel as getting hammered.
While being drunk, Cas says, "Dean-o! Truth or Dare?"
As Dean takes dare, he says, " Go to your room and put on your silliest costumes for a dress up party. Sam and I are gonna take your pictures.
A very amused Sam sent those pictures to Jody and Donna for insurance.
Dean laughs in his mermaid outfit and asks Sam, "Sammy! Your turn."
Sam laughs, "Fine, truth."
Dean says, "So, what does Cas do that annoys you? And don't ya lie."
Castiel pretends to be cool but his heart was racing, waiting to hear what his perfect boyfriend had to say.
Sam giggles, drunk as a skunk, "He pretends to be pop culture savvy and makes a fool of himself, but I go with it."
Poor Castiel's heart shattered as Dean realized his mistake.
Sam mumbled, "Babe, when do I pick you up?"
Castiel says, "I'll get a cab, don't worry." With that, he leaves for his solo hunt.
Sam turns to Dean, unsure of how to fix this whole mess. He can't exactly blame Dean, Dean wasn't the one who blurt it out. Sam could've said anything else, like not washing his socks, the simple stuff. But they both knew how sensitive Castiel was about not fitting in and to hear his own boyfriend say that….
"It's my fault", Dean says with a guilty look.
Sam shook his head sadly, "No man, I'll fix this. You were drunk too, what could you do?"
After that, Cas only replied in absolute necessity and kept ignoring Sam's request to video call. It wasn't until Dean had to personally beg Cas about how Sam hadn't had lunch, when Cas picked his phone up.
"Hey Cas", Sam sniffles but smiles through the phone call.
Cas felt a little bad about the whole issue so he remained as soft as he could, "Hey babe. Does the bunker look empty now that I'm gone?"
Sam says, " Not if the bunker knew when you'll be back?"
Cas sighs, " Listen, I'm not gonna lie, people have died. Bobby is here, helping out. They need me though, to erase people's minds about the whole demon attack. Children Sam, frightened children who don't deserve to be in the middle of this."
Sam nods, " I understand. Just text me whenever you feel like. I won't badger you."
Cas smiles a little, " Hey Sam?"
"Eat your food, you damn fool." Sam smiled at the hint of a smile in Castiel's voice. Maybe they survived their first fight after all.