Cas gripped a lock of Sam's hair and yanked it as Sam licked the cum off of his head. Sam was sitting, crosslegged with Cas' legs straddling his lap with his cock out. Sam made a noise of satisfaction as he cleaned Cas' penis with his slippery tongue. Cas moaned as Sam clutched his ballsack. Sam gave it a slight squeeze and started massaging it. Cas' breath hitched and his chest heaved as Sam sucked his cock and massaged his scrotum.
"You like that, little man whore?" Sam breathed into Cas' cock. Cas tried to catch his breath as Sam stroked it.
"Oh-uh-oh fuck ye-heah I like it." Cas gasped for air when Sam stuck his index finger into his asshole. Sam moved his finger around until he found his g-spot. He started moving his finger back and forth diagonally. Cas moaned loudly, back arching as Sam fingered him. Sam smirked as he saw Cas' cock shoot straight up. Cas clutched the bed sheets as Sam stuck his middle finger in too. Cas cried out in pleasure and bit his lip.
"Oh fuck, Sam. Fuck this feels good." Cas whimpered, eyes shutting and moving his hips a little closer to Sam. Sam smiled and pushed his lips into Cas', fingers still in his anus. Their lips moved rhythmically as Sam pulled his finger out of Cas' ass and pushed him down so that he was on top of him. Sam clutched Cas shoulders as he pulled his lips messily onto Cas'. Their tongues slid into each other's mouths, sliding around their cheeks and teeth. Sam bit Cas' lips playfully and rubbed his nose on Cas'. Sam sucked on Cas' lip, starting to suck his way down Cas' neck. Sam found a spot by Cas' collarbone and sucked hard to make his mark. Cas shivered with pleasure, back arching and hips thrusting into Sam. Sam licked the hickey over and over again and made his way to the other side of Cas' neck sucked some more. Cas buried his face into Sam's messy, sex hair and kissed him sweetly.
"Cas you taste so fucking good, man." Sam choked back a cry into Cas' neck. He grabbed Sam's back muscles and thrust his boner into him some more. Sam sighed, unzipping his pants and taking his cock out, smirking. Cas' breath weakened as Sam automatically stuck it into his ass. His vision got fuzzy as he gasped and choked on his breath. Sam grabbed Cas' shoulder and thrust into him some more.
"Oh my god S-sam!" Cas squeaked, making a fist. Sam thrust faster and faster, both of them gasping for air.
Sam and Cas were done after about an hour more of that. But that was the story of how Cas had the best sex ever with Sam winchester.