Cas didn't want to push his luck. It was enough that Dean paid attention to him, and let him stay, and was his 'roommate.' He was more like a guest in Dean's house. But he was crushing on the man, hard. He found himself watching him cook, and drink, and letting his eyes wander along the curves of his form. His soft waist and the bow of his legs. Cas was noticing things he hadn't before. Smells of a shower starting; the cologne of afterwards; signs of an empty beer. Dean's lips drawing hopefully at the glass lip. It was nuts. He was nuts. He was losing his mind following Dean's footsteps around the house with his ears. Something had to change.
It had been a few weeks longer, and Cas had finished the song. He only practiced when Dean was out teaching though – he wanted it to be a surprise. Of course, he had helped tweak it, and offered ideas, but it was an entire piece that Dean had never heard. Cas was determined to get it perfect. He wanted to see that look on his face again. To prove it to Dean - as well as himself - that Dean felt the same way about him.
He was singing the few snatches of lyrics he could think of under his breath as he did his laundry and cleaned the basement. It was part of the agreement; keep it clean, it's yours. The last thing Cas wanted to do was make things between them rocky because he wouldn't one rule. He teased Dean, and sometimes left it a mess on purpose to tease him, but he also wanted to make it clear that he wanted to stay.
"I am beating in your chest," Cas sang gently, in his deep, gravelly tone. "I am aching with the rhythms. I have lost my grip, on everything I knew."
Dean never did anything personal. He never went out with his buddies, or visited family. He went out, driving for hours, stopping nowhere. Or he went fishing. But he spoke to barely anyone else. Once he'd mentioned that he lost his younger brother in a car wreck and Cas had a feeling it did something to Dean then. There were pictures of him with his '67 before that, laughing with a few guys. There were pictures of him and a beautiful girl, and a young kid that looked like her son. There were pictures of him and his dad, him and his brother, but only one of his mom from a long time ago. But after his brother died, there were no more recent pictures. None. It looked like Dean had bought this place right after and applied to teach and sat on the porch with a beer every night since.
Cas remembered that when he sang the song. He felt every spike of guilt and loneliness like it was his own heart under all that pressure when he picked those electric guitar strings. Like his heart own was being smashed, over and over, with every happy memory fading behind his closed eyes. Like all the things tying him to the rest of the world were severed in a fire that managed to only burn one side forever. Like every morning was a new weight on his shoulders. "We left there and wrecked each other and never looked back," he sang, his voice clear and rich, "I left everything in the worn soles of our shoes. I am beating in your chest, I am aching with the rhythms; and I know you feel exactly as I do." He tricked out a hammer-on from the strings and his fingers flew along the frets. "Beat out the stars, beating them out; twisting me into knots and watching yourself in the mirror fading. But I could never leave – we are never gone. I'm in every step and every chance you take. I am with you. I am with you," Castiel sang. "I am with you." He strummed down once more and let it echo off, fading into the silence of the room.
Cas's heart was pounding. He had nailed it. A great storm of triumph brewed in his belly and rose in his throat, pushing a beaming happiness into his eyes and between grinning teeth. I can't wait to show it to Dean, he thought breathlessly as he unplugged his guitar. Perfect, it was perfect. Motion caught his eye, and he looked up in alarm. His lips parted in shock, eyebrows creeping up.