Cas has got to be one of the most flexible men Dean knows. Most men aren't capable of bending like that and walking away from it. But Cas just folds himself right up like it's nothing. Like right now.
He's holding his own legs down to his chest, fingers clutched to his knees while he's spreading himself wide. A couple pillows are stacked under his hips, tilting him to just the right angle. Dean's hands are splayed out over his thighs, bracing some of his weight while he fucks into Cas' wet hole.
Like always Cas can't stay quiet, he's making all kind of little noises, compressed as he is. Tiny uhn, uhn sounds that make Dean want to soothe him and jack him off til he comes so hard it lands on his own face. Those big blue eyes Dean fell in love with are looking up at him pleading, begging for an end to it.
Dean's loathe to deny Cas a damn thing, especially when he whimpers and is just such a good little boy.
"Say it, baby." He thrusts in hard, almost making Cas lose his grip.
Cas shouts, his knuckles white with the strain to keep himself in position. "Please, Daddy."
Dean smiles and runs his hands down Cas' thighs, right to his hips where his cock is hard as it lays against his stomach. "Please, what?"
A little sob leaves Cas' mouth when Dean gets the angle right and runs over his prostate. "Please make me come, Daddy."
Dean groans and wraps a hand around Cas' cock. "There we go, sweetheart, that wasn't so bad, was it?"
Cas shakes his head and his legs shake, his mouth is open and all he's letting out is ah, ah, Daddy! and Dean is so fucking close as it is. There's not warning when Cas comes, just his dick pulsing in Dean's hand and his hole squeezing Dean's cock desperately. Dean stops just long enough to support himself on his hands at either side of Cas' shoulders. His legs fall to Dean's waist and Dean can feel heels on his lower back, sliding through the sweat that's built up.
He can't control himself, his hips snap forward again and again, jostling Cas on the bed. Over and over he chants fuck, Cas and below him blue eyes are dazed, a wide smile almost making the younger man look drunk. Cas' hands run up his chest, warm and loving on his skin.
"I love you, Daddy." Dean buries himself in Cas and comes, eyes shut tight and throat locked up. He can't breathe, can't scream or moan or anything.
He's sure he blacks out, everything disappearing from around him until he comes to in a sated heap on the bed with Cas curled into his side. He pulls Cas up to straddle him, slow kisses passing back and forth.
When they break Dean kisses his way down Cas' neck, murmuring against his skin. "My good boy, so fucking good for me. Perfect, Cas, you're beautiful."
Cas hums happily and melts into him, his perfect baby boy.