Castiel stared deeply into Dean's vibrant eyes. Their argument, for the time being, seemed to be at a calm. The calm before the storm perhaps. There had been so much tension lately; not just between Cas and Dean, but everyone: Sam, Mary, even Crowley. Something was wrong with Dean, and Cas knew it wasn't just the normal "family business" kind of stress. He was different lately, jumpy and angry, arrogant and aloof. And something else that Cas couldn't quite put into words.
Despite all his anger and disinterest Dean's eyes remained that brilliant green; no, they were somehow greener than before. Like an apple from an old fairy tale. Cas' eyes, brilliant in their own right, searched Dean's for answers. They were arguing about their next move in the search for Lucifer. Dean wanted to not only leave Cas, Sam and Mary behind, but he even declined Crowley's help. While Cas could easily understand Dean's reluctance at bringing Mary, and even Sam, with him, he couldn't wrap his mind around his hesitance towards Crowley and himself. They were both beings of immense power and skill, something Dean could really use.
They were alone in the bunker; Sam had taken Mary for her very first smart phone, and it was likely that Sam would show her all the basics of using it. This gave Castiel an opportunity to confront Dean on his recent actions, and his mood. Not surprisingly, it immediately gave way to a torrent of curses and accusations from Dean. He berated Cas for never giving him, Dean, personal space; shouted that he didn't need Cas, that he was useless with his mangled, broken wings anyway. Castiel was surprised at how much Dean's words actually affected him; he was becoming more and more human-like everyday, and he was realizing how much emotional pain humans can experience at the hands of a loved one.
Cas stood still, his eyes moving to follow Dean as he stomped around the bunker, kicking chairs and swiping research from the tables. Cas narrowed his eyes and tilted his head, trying to understand where Dean's emotions were coming from. Dean took notice, leading to another round of verbal assault, likening Cas and his head-tilt to a stupid dog trying to read a human's mind. Dean stomped over to Castiel, jabbing his strong fingers into Cas' chest with every harsh word. Cas took a few steps back, trying to excuse himself from the physical side of Dean. This only seemed to encourage him; Dean's eyes sparkled and he walked forward, forcing Castiel's back against the wall.
Cas felt actual fear for a moment. He trusted Dean; trusted him with his life, in fact. But there was something wrong, something off in the whole atmosphere. Dean was so close to Cas, his large hands plastered against Cas' chest, pinning him to the wall.
"You're stuck," Dean purred. "There's no getting away without your wings."
Just as Castiel began contemplating whether or not to physically engage Dean, to hurt him to save himself from whatever he had planned, Dean roughly placed his lips against Castiel's. The initial action startled Cas so badly that he pushed even further against the wall, with Dean following, completely destroying any possible space there was between their bodies.
The kiss was deep and so full of feeling. Cas had kissed before, had even had sex before, but this feeling was new and intense. The immense passion radiating off of Dean overwhelmed Cas, and he allowed himself to succumb. Keeping Cas pinned to the wall with his hips, Dean removed his hands from the angel's chest and grabbed the sides of his unshaven face.
There had always been a profound bond between Cas and Dean; Cas felt it but never fully understood it. He knew about bisexuality but never actually considered it. But in this moment, with this overwhelming feeling of pleasure and friendship combined, Cas let his body relax, his shoulders finally slumping and his posture relaxing. He kissed back, tentatively at first and then with more confidence as he let his body mold towards Dean's. As one of Dean's hands moved away from Cas' face, Cas mirrored Dean by letting his fingers trail along Dean's jawline.
Suddenly, Cas felt an excruciating pain on the left side of his abdomen. He broke the kiss, hand still on Dean's face, and looked down to see Dean's hand gripping the angel blade, which was sunk in up to the hilt inside of Castiel. Cas moved his eyes, which were fading from that spectacular blue to a dull lifelessness, back up to meet Dean's; but those poison-apple green eyes had turned black. With a small moan of pain and utter disbelief, Cas felt his eyes tearing as he tried to fight through the pain. He placed a hand on Dean's shoulder, fighting to stay on his feet. A small "Dean" was all he managed to choke out before he sunk down to his knees, his hand trailing down Dean's body, never breaking contact. Before the light went dark, Cas could feel his wings shuttering and burning away; the last thing Castiel saw before it was all over were the coal-black eyes of a demon turning back to the gemstone green ones of his friend. There was the unmistakable shadow of regret behind them. Castiel felt everything tremor and burst around him, and then all was dark.