First, Dean licked the rivulet of sweat from the hollow of Sam's throat. Then he trailed his tongue along the ropy vein on Sam's right arm, starting at the top edge of the bicep, pressing harder at the crook of the elbow until he could feel Sam's pulse. He followed it all the way down to Sam's wrist.
A small turn of the head, and his mouth was right there, at that indentation below Sam's right hipbone. He kissed and licked at it softly, driving a soft moan out of his little brother. He traced his tongue along the edge of Sam's jeans, darting past it just a touch, just to tease. Sam gasped, and pressed his hips up, silently asking for more.
Dean silently told him, "Not yet."
He spent a few minutes working his way slowly up Sam's treasure trail, flicking his tongue into the gentle indentation of his navel, then licking and sucking at it like it was another part of Sam-the part he loved to lick open slowly until Sam came apart under him, shivering and writhing and begging so-very-out-loud for Dean to... oh, for Dean to do so many things. Put his fingers inside him. For more. For him to fuck him, hard as he wanted. For him to let Sam come. (and that was Dean's favorite. That was the point of the whole damn exercise-getting his strong, capable little brother to beg Dean to let him come. Because Dean's favorite words out of Sammy's mouth were "Dean... please."
Dean licked and sucked and teased Sam's belly button until Sam was fisting his hands in the sheets, sweat sheening his chest, arching up into Dean, making the sweetest little rough moans. But Dean didn't so much as touch Sam's cock.
He peeled Sam's jeans off, pushed him back down on the bed, straddled Sam, naked and erect, and held himself up, just a few inches above Sam. Held himself there-and wouldn't let Sam touch him.
"Hold still, Sam. Just fucking hold still. Take what I give you."
Sam erupted in a full-body shiver, and stared up at Dean. But he did what he was told.
Dean lowered his head and lapped at Sam's chest, savoring the taste of salt on his skin. He took a nipple into his mouth, brought his teeth down in a gentle bite.
"You want me to fuck you, Sammy?"
Sam bit his lip. "Yeah."
Dean's mouth twitched. "Gotta earn it."
Sam swallowed hard. "Whatever you want."
"Damn straight. And right now? Wanna see how much you can take." He brought his teeth down on Sam's nipple and slowly, so very slowly, increased the pressure.
A little more pressure.
Sam made a tiny sound.
Dean increased the pressure a little more.
"Fuck." Sam panted. A trickle of sweat ran down his neck.
Dean ran his hand up the back of Sam's neck and tangled his fingers in Sam's hair, squeezing, pulling Sam's head back, and bit down even harder.
Sam let loose with a half-cry, half-growl, digging his fingers into Dean's shoulders hard enough to bruise.
Dean could almost taste it. He had Sam right there, on the edge of too much. The edge of "I can't."
Sam hovered there for a long moment-then he surrendered to Dean. Surrendered to the pain. With a single, graceful motion, he arched up into Dean's mouth, pressing himself into Dean, digging Dean's teeth into his flesh even harder, letting his hands fall limp at his sides.
"Yes. Yes. Yes."
Dean parted his mouth, releasing Sam's nipple only to seize it with his fingers and pinch brutally hard. "There it is, baby boy. So good. Taking it so good for me." He kissed Sam, taking his cries into his mouth, tugging and pinching.
"Fuck. Dean. Please. Christ. Please let me come. Wanna come for you. Please."
The feeling that roared through Dean in that moment was almost better than a physical orgasm. Sammy. His...fuck, his everything. Begging for it. For Dean.
"Ok, Sammy. You earned it." Dean pumped a jet of lube into his palm from the bottle on the end table and slicked Sam's cock. He drove his tongue deep into Sam's mouth. Sam sucked on it, moaning, fucking up into Dean's hand, his tanned body gleaming with sweat, writhing and moving like a high-end porn star.
Dean pulled his mouth away from Sam's. "Sam. Come for me." Dean sealed his mouth over Sam's other nipple, and bit down hard, working his hand over the end of Sam's cock.
And Sam fucking screamed, thrashing beneath Dean, head tossing from side to side, coming hard, hard, harder, come shooting with enough force to spatter the underside of Dean's jaw, his own face, even the headboard.
"So fucking beautiful." Dean just stared at Sam's face, watched the expressions of pleasure contort it.
He might have forgotten about his own need to come, lost in how majestically gorgeous Sam was when he came. But Sam didn't.
A swift motion, and Dean found himself flat on his back, Sam between his legs, stretching his thighs wide open with his massive hands, pressing them up and back, and his mouth fucking devouring his cock, moaning as he sucked his big brother down, moving one hand down to tug at his balls the way Dean loved.
Anybody would have come in 30 seconds, with what Sam was doing with his mouth and hands. No shame in that.
No shame at all.
And Dean was shameless, spreading himself for his baby brother, staring at him in wonder, saying so very many sweet/filthy things (jesus fucking christ sam fucking born to suck my cock fuck fuck feels so good Sam your mouth feels so good christ could do this forever gonna fuck you all night baby boy all fucking night that's a promise fuck Sammy gonna come gonna fucking come down your throat oh god Sammy Sam SAM) until he came chanting Sam's name, as he always did, always would.
And when they'd both recovered, Sam held Dean to his promise.
All night long.