Sometimes Castiel wondered how far he could push Dean before there was resistance. As it was, Dean simply did as told. Kneel, and he was on his knees, looking up at Castiel, just waiting. No human should have had this power.
Castiel cupped Dean's face in his hands and gently stroked the arches of his cheekbones. It was odd, the way the curve of Dean's skeletal structure looked so much like the bones of an old church. What must he have looked like to Dean? The sight of an angel was more encompassing than that of a human, more total. Were there scars on his soul, or did Dean heal him entirely?
The pad of his thumb brushed over the softness of borrowed lips. In times like this he couldn't bring himself to ask questions, to wonder who it was Dean was possessing.
Open, and Dean's wings appeared as his lips parted. The high Castiel got from this was unholy. He was using a creature of God, something made of power and faith and love. Most parts of him wanted to turn away from it, to revel in the guilt of defiling something so glorious. But Dean grabbed his hips and pulled him closer before he could. He didn't know if Dean read his mind or his face, but the message was clear: Castiel wasn't forcing Dean to be here, to do this.
The zipper on his jeans opened on its own, Dean adopting a lewd smirk as an admission to his abuse of power. Castiel undid the button on his own, eyes tracking the movement of every twitch in Dean's silver wings. The copper freckles looked so much more luminous when the feathers were soaked with oil.
His pants and boxers were dragged to the floor, Dean's hands warm on his legs as they slid back up and under his shirt. A gentle kiss was pressed to the shaft of his cock, more blood rushing down to fill it. Sometimes Castiel thought his blood was the only thing he had left. At least it could be of use.
Dean frowned up at him and kissed his hip, a bright spark of Grace flashing in his pupils. The first touch of Dean's wings wrapping around him made him gasp. Despite the metallic appearance and strength of the feathers, they were soft as the wind on his skin. Warmth bled into him from every point of contact and if he'd had the energy or will, he might have fought it. As it was, the only being he knew more stubborn than himself was Dean and Dean was always so intent on serving him, making him feel good.
Castiel's eyes slipped shut when Dean pressed a kiss to the head of his cock, tongue flicking out across the slit. In the self-inflicted darkness Dean's touches were more intense, so much better when he couldn't see. He pitched forward as Dean sucked him in, strong hands splayed wide on his hips.
This was his second favorite act of blasphemy to commit together. The first involved Dean on his back, wings spread wide and destroying the room while his body accepted Castiel's rough thrusts like the hammering of nails, drank his release like communion wine. Though maybe it was more accurate for this, for Dean stopping half way down and relaxing his jaw, an open invitation.
The only command Dean would ever give him was spoken to his mind instead of his ears. Look, and he opened his eyes. Green irises glowed with the white of Grace illuminating them from behind. Shafts of it shifted and pulsed and Castiel wondered if he put his hand over Dean's eyes if he would feel it burn him. I'd never hurt you, Cas.
Castiel smiled and accepted the openness of Dean's mouth and throat like the openness of his service. His fingers tangled in Dean's hair as he began to roll his hips, amazed at how coarse it felt in comparison to the feathers cradling him. Humanity was a rougher thing, though.
He never feared hurting Dean like this, not by thrusting too fast or hard. If anything, Dean encouraged him to lose control. Any parts of himself he'd normally hold back were free to writhe and scream. Filthy words poured from his mouth as he snapped his hips and rolled them to slowly pull himself back out. Spit covered his skin and dripped down his balls, a good bit of it also smeared across Dean's face.
The freedom he found with Dean made him drunk. Swallow me, angel. Things he never thought himself capable of thinking, let alone saying. Drink me, Dean. Every syllable of sacrilege made him harder, made his balls feel heavier and his skin tighter. Prove your devotion. He never thought about it afterward, never. You're mine, all of you.
Dean's arms wrapped around him and held him in place, the head of his cock surrounded by the fluttering of Dean's throat as he swallowed over and over. The tip of the seraph's nose was smashed into his hip, ground further with the motion of a nodding head. Subtle whispers formed within his ears, barely there below the carnal sounds filling the room. I'm yours.
Castiel shouted and came at the words, knowing in his heart that he was hearing Dean's true voice. That he was hearing the prayer of a lost warrior trying to find his way to a new God.