It hadn't been Sam's fault.
At least, that's what he kept telling himself.
It was a rainy day. Hours upon hours of endless research, and the younger Winchester had not found them a case.
Just grand. Dean was going nuts after being stuck in that Hellhole without a case. It had been four weeks. Four fucking weeks since their last case. Dean was having none of it.
They were stuck in the Bunker. Dean, Cas and himself, with nothing to do but watch old movies and play cards. It was windy outside; the rain tapped on the windows without any real sign of stopping. Dean suggested they go for burgers and drinks, but Sam knew leaving the bunker would not be wise with Cas in his current state.
Castiel was still recovering from the fall, which was a slow and painful process. Cas, being Cas, hid away most often and tried not to let Sam or Dean see how broken he was.
But Sam knew. He saw pained blue eyes and trembling hands. The angel no longer held himself up like a brave warrior, but a defeated soldier.
Which he was.
Dean paid attention to Castiel's every move. Since the fall, Dean had also changed quite a bit. He rarely let Cas out of his sight, and when he did, he worried. He never said any of his fears for Cas aloud, but Sam could see it written all over his face.
The hunter and the ex-angel grew closer over the next few weeks. On this particular rainy day, Sam couldn't help but notice more prominent displays of affection.
They were going to watch Jurassic Park 2 since the night before was number one. Sam left the living room a minute to go get beer. When he returned, Cas was leaning against Dean's shoulder. His eyes tired, but content. A small smile played on his lips. Dean mirrored his expressions, a smile etched onto his face. Sam smiled to himself before coughing to snap the two out of their loving haze. That left Dean flustered, his cheeks tinted a shade of red.
A few hours later, Sam returned from the convenience store down the road. He carried in a six-pack, a box of a dozen powdered donuts, and an assortment of fruits. And, of course, a miniature apple pie for Dean. Sam stepped into the vacant kitchen and set down his things. He sighed.
The bunker was silent for a moment.
Then Sam heard a noise that sounded like sobbing. Or shouting.
He stepped into the hallway, lingering by the kitchen. The noise only grew louder. He listened, curious, before heading down towards the source. The bunker was quiet again. That changed after a few moments.
A deep, flustered "Dean!" came from Cas' room. Sam rushed down to Castiel's doorway. He didn't even think to knock, flinging the door open with worry.
Sam made a noise like a disturbed animal.
He froze, and stood for a moment, eyes blown wide in horror.
"Oh.. God... nope, nope nopeee..."
Dean was on his stomach, pressed against the bed. Neither one of them wore any clothes, and they were such a hot, sweaty mess. Cas had his hands firm against Dean's hips. His naked pelvis pressed to the hunter's ass. Dean had a look of pleasure on his face, with Cas rutting his hips. Dean opened his eyes wide and turned his head towards the opened door.
"Ugh! Dammit, Sammy! Couldn't you have knocked?"
Sam scrambled for words. "I- uh- Dean- I'm really, really sorry- I thought you were fighting-"
Cas chimed in, his voice husky. "Dean and I can take care of ourselves, Sam. I do not believe humans like being caught in such an intimate position with their partners... Dean?"
Dean laughed, the sound coming out deep and needy. "No Cas... they usually don't." He paused, giving Sam a look. "Just go, Sammy. We have unfinished business."
Sam nodded and shut the door as quickly as possible. "Gross, Dean!"