Title: Catalyst

Author: Wincesteriffic Kaz

Info: A witch lays a curse into Sam's skin that could change things forever. Dean/Sam

Author's Note: Nope. Absolutely no idea how many chapters this is going to end up with. I'm honestly just having fun playing here in between chapters of my case!fic so who knows. Lol Wincest. m/m D/s

Graphic depictions within.

Disclaimer: I don't own 'em but if I did…they'd never get dressed. Heh heh heh

~Reviews are Love~

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Chapter 2

Dean stood at the bar and knocked back another whiskey, watching his brother across the room with his head hunched over his laptop. It had been a day since the…incident…in the forest and he was still trying to find the moral outrage and epic level freak out he was sure he should be feeling. He'd had sex with his little brother. Yeah, it had been to save his life and ok, when he was honest with himself, it was quite possibly the most intense orgasm he'd ever had in his life but still… Dean sighed and smirked with the memory. Intense didn't begin to cover it and then he frowned again.

"Why am I not freaking out about this?" Dean asked himself softly and signaled the bartender for another shot while he watched Sam's dark hair fall into his face, his nimble fingers curl over the keyboard and the arch of his throat that Dean suddenly had the desire to chew on. "Make it a double."

Sam flicked his eyes to the side to find his brother and could practically feel Dean watching him. He'd spent most of the day trying to track down their witch again but was now digging into tattoo symbology to find an explanation for what had happened because, though Dean obviously thought what had happened was over, Sam knew better. He hadn't been sure at first but the last six hours or so he had felt…off. Now for example, as he turned his head to look away from his brother but could still sense Dean across the room; feel his presence like a physical line tugging from the center of his gut to his brother. It was comforting and unsettling at the same time and so very far from human.

Sam wondered how his brother was handling what had happened. In typical Dean fashion; he wasn't talking about it and was basically carrying on as though it had never occurred. Sam sighed. He couldn't decide how he actually wanted Dean to be handling it. Hell, he'd yet to make up his mind how HE was handling it. Sam straightened and turned his gaze to Dean in earnest as a woman moved up along his brother's side and swayed against him. There was a moment where Sam simply rolled his eyes at his brother's ridiculous ability to attract women, like he always did and then that alien feeling rode down over him and he was swamped in a morass of possessiveness and jealousy. He watched her hand trail up the center of his big brother's back and a growl trickled out between his lips as he slid off the stool.

"Really, honey. Any other time, I'd be more than happy…" Dean sighed and looked down at the attractive woman trying to get his attention but there was no way he was leaving his brother until the witch was dead. "Maybe some other…" He broke off when he heard a growling snarl behind him below the level of the music and turned in time to watch Sam stalk to him and slide against him. "Whoa. Sam? What?"

"Mine." Sam's voice came out in a rolling growl and he leaned down into the woman's face as he pressed himself into his brother and slid an arm around Dean's waist.

"Sammy, what the hell?" Dean's eyes widened with concern and he looked over at the woman who backed up a step from Sam's fierce gaze. "Uh, you should go." He could feel Sam practically vibrating against him and put an arm around his shoulders to move him away from her. "Come on. Move, dammit."

Sam let himself be pushed and steered toward the back of the bar and down the narrow hall toward the bathrooms where finally he balked. "Stop."

"Like hell." Dean glared, kicked open the men's room door and shoved Sam inside hard enough he stumbled. "You wanna tell me what the hell that was?" He demanded as he shut the door and slammed the lock home.

Sam's chest was heaving for breath. He could still smell the woman on his brother even from across the room and it burned in his nose. He shook his head in confusion. "I don't…I don't know."

"Take it easy." Dean ran a hand through his hair and watched Sam pace the room, back and forth, like a caged animal and the comparison wasn't lost on him. His eyes narrowed. "Sam? We broke the curse, dude. What's goin' on with you?"

Unable to resist any longer, Sam went to his brother and dug his fingers into Dean's waist while he pushed his back into the door. In his mind, that other being…the leopard…stretched and woke. "It's still here." He whispered and lowered his head to Dean's neck, burying his nose behind his ear and breathing deeply of his brother's scent.

"Fuck." Dean breathed while shock coursed through him and Sam's mouth behind his ear sent little bites of pleasure through him. "Sam…dude, come on." He took his brother's shoulders and pushed him away while Sam's fingers curled into his hips. "This isn't you."

"Can't." Sam lunged forward and caught Dean's bottom lip between his teeth. He closed his eyes on a groan with the taste and thrust his hips into his brother's.

Dean sucked in a breath with Sam chewing on his bottom lip and grinding against him. He fisted a hand in the back of Sam's hair and pulled, getting a needy whine from Sam as he let go of his mouth. "Sam, stop."

Sam tried. He bit his own lip and stared at Dean's chest as he tried to control the lust burning through him but the thing in his mind wanted more and it rolled over him. He shook his head in denial but couldn't stop another growl bubbling past his lips.

"Oh, I am gonna mess that bitch up when we find her." Dean said angrily and gasped as Sam suddenly went to his knees. "Sammy? Are you…" He trailed off when his brother's mouth closed over his cock in his jeans and he blew out a breath. "Oh…ok. Uh, no…dude. Sam." He took hold of Sam's hair again, trying to get his attention but as Sam's blue-green eyes turned up to him, it was clear Sam wasn't driving the bus at the moment. "Shit."

"Need it." Sam gasped and curled his fingers in the top of his brother's jeans. He pulled, popping the button and tearing them apart as he tugged them down. "Need you." He heard Dean speaking above him, felt his fingers pulling at his hair to stop him but it only spurred him on and he closed his mouth over the head of Dean's cock with a soft moan because no matter how much he was arguing, Dean's body was definitely on board with this.

"Shit!" Dean gasped and his head thumped back into the door as Sam swallowed around his cock. His knees went weak and he was thankful for the door behind him or he'd have gone down. "Holy crap. Sam…s…stop." His protest was half-hearted at best with the wet heat of Sam's mouth around him and his tongue curling along the underside of his dick.

Sam threw himself into it, hollowing his cheeks as he slid more of Dean into his mouth and a purr rumbled up out of his chest.

Dean's knees went dangerously weak when the purring started and the vibrations pushed him from fighting to helping. "Ah g…god." He jerked his hips, pushing himself deeper into his brother's mouth. The wrongness of it escaped him again, melting away with the feel of his brother's mouth and hands.

Sam pressed a hand into his own straining erection as he sucked on his brother's, purring and moaning, sliding Dean deeper until he bumped the back of his throat. He wrapped his other hand around the base of Dean's cock, holding what he couldn't fit in his mouth and squeezed as he pulled back up and dug his tongue into the slit. He felt Dean's legs tremble and his fingers dig harder into his hair and Sam groaned, picking up his pace.

"Fu…fuck, Sammy. I'm…" Dean edged toward panic as his orgasm crept all too quickly up on him. He was so close. He was gasping and stared down at the top of his brother's head trying to urge him off. Sam's eyes rolled up to his with hunger clear in them, Sam rumbled another purr around him and Dean was lost. He cried out hoarsely and thrust his cock into Sam's mouth as his head went back. The breath stuttered out of his lungs with Sam sucking hard and working him through his orgasm, drinking his come with noisy, greedy swallows. Dean's legs had had enough and he slid slowly down the door until he was sitting on the floor with his legs spread wide around his brother and his head spinning dizzily. "Holy…crap."

Sam let his brother's softening cock slip out of his mouth as he slid down the door. He wiped a hand over his lips, savoring the taste of him on his tongue and climbed into his lap. "Dean." He breathed and curled down until his nose was behind Dean's ear again.

Dean let his head rest on his brother's shoulder, still too spent from coming that hard to do more than curve his hands around Sam's hips and pull him in. "You in there again, man?"

Sam nodded and bit gently behind Dean's ear. He ground his hips into Dean, trying to find some friction for his own cock, still trapped in his jeans and aching with need as he bit and licked the sensitive skin of Dean's neck.

"Sam. Talk to me." Dean managed to raise his head and slid his fingers into his brother's hair. "Sam." In response, Sam let his head roll to the side, offering up his neck to Dean with a shiver. "Shit." Dean whispered because this was definitely the thing inside him still talking. "Ok. Alright." He took a breath and bent his head, sinking his teeth into the side of Sam's neck as hard as he had the day before. Sam shuddered with a loud, moaning whine and went lax against him, breathing heavily. Dean frowned and pushed a hand between them, surprised to find a warm, wet spot growing in the front of his brother's jeans; biting Sam had made him come. "Holy shit that…that's kinda hot dude. Wow." He mouthed the words into Sam's skin.

"Mmf." Sam grunted as the fog began to lift from his mind. He smiled lazily, still breathing against Dean's throat and then registered the uncomfortable feeling in the front of his pants and the taste on his tongue. He reared back with wide eyes, grateful for Dean's arms keeping him from sliding to the floor in a heap. "Oh, god. Dean?"

"Hey, hey. Take it easy." Dean soothed and held on to him, waiting until Sam's eyes settled on his and was relieved to see his little brother looking back at him even as he squirmed in his grip. "Settle." He said and tightened his hands on his brothers' shoulders.

"Sorry." Sam closed his eyes and took a breath.

"Obviously, that witch bitch didn't tell us everything. Break the curse, my ass." Dean groaned and gave Sam a little shake. "You and me, we're gonna get out of here and we're gonna find her. Got it? You're gonna be ok."

Sam nodded and shifted, getting his legs under him. He stood and then reached down to pull Dean up as well. "Yech." Sam groaned and pulled the damp, sticky denim away from his crotch.

Dean smirked and tucked himself back in his jeans. "Brought that on yourself, dude. What the hell happened anyway? You remember?"

Sam nodded, tugging his flannel down to cover himself. "Um…I was, well I mean the leopard, it…" He sighed and rolled his eyes. "How come I have to be the one with a jealous, horny cat in his head?"

Dean snorted and smothered a laugh as he unlocked the door. "You know it's gonna kill me not makin' pussy jokes at your expense right?"

"Oh, my god. Can you shut up now?" Sam rolled his eyes even as he smirked and followed him out. His cheeks flushed bright red as he walked past a short line of people who had been waiting and, judging by the knowing and amused looks on some of their faces, were in no doubt of what had been going on in the bathroom. "I wanna die." Sam groaned.

Dean chuckled and pulled him back out into the bar, grabbed the laptop Sam had left and that was thankfully still there and gave him a shove toward the door. "Come on, before any of the locals decide they need to teach us a lesson or something." There were definite unfriendly looks from some of the more redneck men in the bar and he quickly ushered Sam ahead of him outside. "Cross this bar off the list of places we can hang at." He said ruefully.

Sam was still stuck in his head, going over what had happened…twice now. The sense memory of Dean's cock in his mouth overwhelmed him for a moment and he felt the cat in his head stir and growl contentedly. "Fuck."

"Sammy?" Dean moved so he could see his face as Sam stumbled to a stop with his eyes closed. "You alright?" Concern overwhelmed him for his brother and whatever was happening to his mind and body.

"I'm good." Sam nodded and made himself keep moving, going to the car. He didn't want to explain to his brother that it had been the memory of tasting him that had almost brought him to his knees in the parking lot. He took the laptop Dean handed him and got in the car.

Dean closed the door on him and shook his head because he was pretty sure Sam was far from 'good'. He looked up as the bar door banged open and saw three men stride out with angry faces and fix on him. "Ok, time to go." He rushed around the car and behind the wheel, peeling out of the parking lot with the men glaring and shook his head. He was going to have start picking more…liberal minded places for a drink if this was going to go on for much longer because Sam's current respect of his personal space left a lot to be desired.

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Sam rolled to his back on his bed and stared at the ceiling. He couldn't sleep and listened to Dean's deep and even breaths in the other bed and tried to ignore the itching in his own skin to crawl in beside him. The other presence in his mind was waking again, stretching inside him uncomfortably and it reminded him of what he'd felt in the forest when his bones had started shifting, joints popping and the agony he'd suffered that only Dean's touch had soothed. He blinked and realized he was no longer in his bed; he was on the floor between them with one arm stretched up and a hand wrapped loosely around his brother's arm.

"Shit." Sam whispered fearfully. He didn't remember moving and let go of Dean, drawing his arm back down and curled around himself to lean against the side of his brother's bed. The cat in his head wasn't pleased and Sam could almost hear it hissing at him with irritation. Hunger roared to life inside him and Sam had the sudden realization that the leopard wanted food or sex and Sam would have to decide. He shuddered because he knew; food didn't mean have a burger…it meant find someone to eat. "No, no, no." He closed his eyes as his stomach cramped and started rocking.

Dean jerked awake and raised his head, trying to determine what had woken him as he looked blearily around the darkened room. He turned his head over to his brother's clearly empty bed and sat up in a rush. "Sam?" A soft noise, like a choked sob, drew his eyes down and he found Sam pressed against the side of his bed on the floor, arms wrapped around himself and rocking back and forth. "Sammy?" Dean put a hand down on his brother's shoulder and a shudder passed through Sam. "Dude, what's wrong?" He had a feeling this was going to lead to another boundary issues episode and took a breath to relax. If it had to happen, he'd let it because it was Sam and Sam needed help; he needed him. "Come on. Come're." He pulled at Sam's shoulder.

Sam sucked in a pained breath and let Dean pull him up. He shook his head and leaned heavily into Dean, wrapping his arms around his chest and taking them both down to the bed. "It's awake."

"Ok, I get that but what's goin' on?" Dean stiffened for a moment and then relaxed into the embrace, folding Sam in his arms and trying not to notice how happy parts of his brother suddenly seemed to be as his obviously hard cock pressed into Dean's hip.

Sam burrowed his head under his brother's chin as the hunger twisted in his gut but being that close to his throat, Sam could hear and almost taste his pulse and the blood flowing underneath it. It made his mouth water and he panicked, rearing back. "No!"

"Sam! Dammit." Dean grabbed him before he could topple off the bed and rolled, trapping Sam under him. "Talk to me right the hell now!"

Sam heaved for breath and turned his head away from his brother's temptingly close throat because the thing inside him…was still hungry; it wanted blood. "I…it wants…god, Dean! Let me go!" Sam pushed, trying to get away and curled his hands around his brother's arms, not wanting to leave him at the same time. "Blood. It wants blood and I can't! I can't!"

Dean saw Sam's lips curl back from his teeth in the sliver of light between the curtains and felt him trembling under him. "That all it wants?" It was an easy decision in his book. As long as it wouldn't kill him or leave him permanently scarred…well, more permanently scarred than screwing your little brother was going to make him, he was alright with it. "Sam."

"No." Sam whispered and his hips rolled up into Dean's without his conscious thought, the creature in his mind making the decision for him. His breath came in short pants as he turned his face back into his brother's throat.

Dean groaned with the feel of Sam's cock rubbing against his own through their sweats. Heat flooded him and he wondered if somehow, some of the damn curse hadn't rubbed off on him because he wanted Sam in that moment every bit as much as his brother wanted him and the guilt and the fear once more flowed away as he let his head fall and took Sam's lips with his own. "It's ok, Sammy." Dean breathed against his mouth and swallowed the soft sob of relief that broke loose from Sam. He took Sam's face in his hands and deepened the kiss, sweeping his tongue into his brother's mouth and tasting him.

Sam moaned and let his hands slide down Dean's back as the leopard's attention turned from blood to sex and the purr he was starting to become comfortable with rumbled up out of him as he curled one leg over his brother's hips to pull him closer. He sucked Dean's tongue into his mouth and smiled in pleasure when Dean shivered over him.

"Shit, Sam." Dean moaned and bit along his brother's jaw, down to his neck while he trailed a hand down his side and rucked up his brother's shirt. He bit along Sam's now incredibly responsive throat, making his brother arch up into him and smoothed his hand up Sam's chest to pinch a nipple between his fingers.

Sam gasped and threw his head back. He pulled at Dean's shirt, at his own, shoved at his brother's sweats, desperate to not have clothing between them any longer.

Dean chuckled breathlessly and sat up, straddling Sam to pull his own shirt off. He tugged Sam's off when his little brother reared up for him and then pressed him back to the bed. "Settle down." He smiled and bent, taking one of Sam's nipples in his mouth. He sucked and rolled it hard between his teeth while he inched back and took Sam's sweats with him, baring his hard cock. He brushed the palm of his hand over the head and grinned as Sam's hips bucked up into his with a needy whine. "Fuck, I love the noises you make, Sammy." Dean slid further down his brother's now writhing body, licking and nipping with his teeth and tongue at every inch of flesh underneath him.

"Dean!" Sam shouted his brothers' name when he took his cock into his mouth, sucking hard at just the head. He was able, at last, to push the cat-mind back enough to have some control and more than a little shocked with himself to discover that he didn't want to stop this any more than the leopard did. He bucked his hips and curled his fingers into Dean's short hair. "G…god, don't stop."

Dean moaned happily and pulled off to look up at his little brother. He felt a little better knowing that this time, Sam appeared to be in there and not just a ride-a-long. "I gotcha, little brother. Stay there." He slid off the end of the bed and into the bathroom. He came back out with the bottle of motel lotion and peeled off his sweats while Sam watched with hungry eyes that made him shiver. This time, especially as the cat didn't seem to be so completely in control, Dean was going to make sure he did this right.

Sam rose up, hands clasping at Dean's shoulders and he dove into his mouth. He licked along Dean's sensuously full lips and tasted himself there with a groan as lust swamped him. "Hurry. Want you." The purr vibrated up out of his chest again as he felt his brother's hand slide between his legs and Sam opened them wide, canting his hips up wantonly.

"Jesus, Sammy. Killin' me here." Dean groaned loudly into Sam's throat and bit him, knowing Sam wanted his teeth as much as his fingers and slid a lotion slick finger inside his brother.

Sam's whole body shuddered and trembled, back arching as Dean pushed a finger into him. The sound that came out of him was a loud, growling moan of pleasure and the thing inside him agreed. "More!" He rocked his hips down as Dean pushed two fingers into him and rolled his head, baring his throat. The cat in his mind knew it was a submissive gesture and Sam didn't care. Dean needed to be in control of him; that was clear as day to him. The leopard in his mind needed to be controlled or Sam would be ripping throats out.

Dean closed his teeth over Sam's pulse and sucked, pulling blood to the surface and making Sam whimper desperately as he moved three fingers in and out of his brother, scissoring them and opening him up while Sam's hips rocked back onto him seeking more. He pulled his fingers from his brother, keeping his grip on his neck with his teeth and slid his hand over his own cock, slicking it and then pressed it to that now loosened ring of muscle. He groaned into Sam's neck as he pushed into him and rocked one of Sam's knees up on his elbow.

Sam cried out with the feel of Dean's cock pushing inside him so slowly. He rolled his head once Dean released his teeth and clawed his blunt nails down his brother's back.

Dean leaned up on arm to watch Sam as he pushed into him completely, resting against the warm cheeks of Sam's ass, pulled out temptingly slow and then slammed back in. Sam rose off the bed as Dean hit his prostate and shouted. "Fuck!" Dean grunted and had to fight the urge to come as Sam's muscles clamped down around him and the vision of him writhing, crying out, whimpering and now begging for more and faster…Dean shuddered and pulled out again to drop his head to Sam's collarbone with a gasping laugh. "Gonna make me…come…like a friggin teenager here, dude. Shit!"

Sam whimpered with the loss of him and dug his fingers into the muscled cheeks of Dean's ass. "Please…fuck, please. Don't stop! Dean, please!"

Dean leaned up and pulled Sam's hips into his lap, smiled down at him and slid fluidly inside Sam again. His breath caught in his throat as he hit Sam's sweet spot again, the muscles inside him clenching and releasing around Dean's cock as Sam rocked his hips back and took him deeper. "So hot, Sammy. Fuck, look at you." Dean let his eyes roam his brother's chiseled, straining chest; drew his fingers through the sweat glistening on his skin.

Sam was nothing but sensation now; nothing beyond the feel of Dean's cock shoving in, pulling out and coming back again. He wrapped his legs around his brother's waist and pushed up, grabbing at Dean's arms until he was sitting in his lap. He dropped his head back on a growling cry as the angle changed and Dean went even deeper inside him.

Dean pulled Sam into him, shivering as he felt that purr rumbling through his brother's chest and into his. He thrust up again and again into him, his rhythm beginning to falter as his climax neared. Dean reached between them and wrapped his free hand around his brother's cock. "Gonna come for me, little brother?"

Sam gasped at the endearment, the timing of it, the wrongness of it and felt like his entire body seized for a moment as Dean slammed up into him, filling him and twisted his wrist just right on his cock and then he was screaming out his pleasure, convulsing forward and only Dean's grip around his waist kept him from collapsing as he rolled backward and his back bowed over the bed.

Sam falling back over his arm in a muscled, straining arch as he came screaming was it for Dean. His orgasm slammed into him and stole his breath on a drawn-out cry of his own as he pistoned up into him again and again and came hard enough to see white and worry he was going to pass out with the strength of it. Finally, it eased, small after-shocks wringing another twitch of his hips and he eased Sam's back to the bed and stretched over him. "Shit Sammy." Dean groaned with feeling and lay beside him. He stared in surprise, brushing the hair from his brothers' eyes with the realization that Sam…was out cold.

Dean chuckled and pulled his brother over and half onto his chest. He smoothed a hand comfortingly up and down Sam's back, still heaving for air and closed his eyes as he came down from yet another explosive orgasm. "Can't…come like this…all the time, man." Dean shook his head and rested his chin in his brother's sweat-damp hair. "We'll friggin die."

"Happy though." Sam's voice came muffled up from Dean's shoulder.

"Hey. You ok?" Dean palmed the side of his face and felt Sam smile into his hand as he nodded and slid a leg over his brother's.

"Better than." Sam mumbled. He was boneless with spent pleasure and, like in the forest, wasn't planning on moving anytime soon. The cat in his mind was well-sated and sleepy. Sam nuzzled his face into Dean's chest, breathing in the smell of him. "Sleep."

"You're giving in to the stereotype here, dude." Dean laughed softly, thinking about how many women accused men of sleeping after sex. He didn't argue though, just as happily exhausted and wrapped his arms around his little brother who had already fallen into sleep.

"I had to see it for myself."

Dean jerked in shock and half rose with Sam still against him to find the witch at the end of the bed. "How…"

"I honestly didn't think you'd do it." She chuckled and waved a hand and Dean found he couldn't rise from the bed or even move his arm to grab the knife under his pillow. He snarled with rage at her. "Your own brother. I am impressed."

"I get off this bed and you're gonna have a hell of a bad night, bitch!" Dean shouted and Sam started to stir against him.

The witch snorted and sat on the end of the bed, running a wondering finger up the back of Sam's calf. "I really would have liked to make him one of mine but I begin to see he probably would have killed me anyway to get back to you." She smiled at Dean's possessive growl and licked the end of her finger. Her brows rose and she stared at the two men in renewed fascination. "Oh, my. What have you done to each other?"

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To Be Continued…