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: Alright last chapter! :D Probably. This one does contain a brief episode of Non-Con and some disturbing imagery. Don't read if you don't like it. 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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"You look awful unconcerned for someone with two guns pointed at her head." Dean said darkly and didn't like it one bit when she laughed. He saw Sam twitch from the corner of his eye and knew his brother felt the same. He tilted his head, cracking his neck and decided fun time was over. Dean pulled the trigger. The bang of the gun covered the sound of his gasp as the witch was suddenly not standing there anymore, replaced instead by the most massive leopard he'd yet seen. The bullet sailed far over her head and then she was leaping toward him.

Sam swung, trying to follow the blurred path of the witch as her leopard form jumped for his brother and fired. He knew he hit her; saw her body jerk with the hit but it wasn't a kill shot. "Shit! Dean!" Sam yelled and moved, trying to find a clear shot. He was so focused on saving his brother he didn't register until too late the sound of movement behind him. Sam only managed to half turn his head before two of the witch's leopards bowled into him and rolled him across the clearing in a tangle of limbs and snarls. All the while, his focus was still on Dean struggling beneath the witch and trying to keep her massive jaws from his throat. "DEAN!"

Chapter 4

Sam sprawled in the grass and rolled to his hands and knees as the big cat in his mind roared to life with the scent of blood. He snarled at the two leopards standing between him and his brother. He saw his gun lying a few feet away and tensed, waiting for the cats to attack. They sprang and Sam leaped aside, hitting the ground and rolling. He came up with his gun in his hand and fired, shooting and hitting each cat in the head as they turned and the sudden, heavy smell of blood in the air made his mouth water. Sam spun to get to his brother and a growling cry burst from his mouth as three more of the cats stood in his path.

Dean heard his brother fighting beyond him as he fought to hold the witch at bay. Her feline jaws snapped and hissed in his face. "Lady…get…get a breath mint!" He bucked his hips and slammed a knee into the leopard's side and felt warm blood seep into his knee. It made him grin; Sam had landed a good shot even if he hadn't killed her. "Bitch!" Dean pushed his head back into the ground as her muzzle was suddenly millimeters from his face and her fierce, yellow eyes bored into his. His eyes went wide in shock and a little fear when he felt his limbs become leaden, as they had that morning when she'd held him immobile. His arms and legs fell to the ground and he lost the ability to move once more.

The witch shifted atop him, returning to human form in the space of a blink, and her face was a mask of contained rage and pain as she glanced at the bleeding hole in her side. She turned her head to find Sam, satisfied her pets had him sufficiently distracted and turned back to Dean. "You could have left me alone." She hissed it at him and leaned down to lick along his jaw that quivered with anger. "I was content to leave you both be, but no…" She dropped her hips to his own and raised a brow, feeling the unmistakable bulge of his cock. "…you had to come after me and now…now I'm going to take what I want."

"Get the fuck off me!" Dean snarled it up at her helplessly while her hands trailed down his chest.

She chuckled. "I can feel your brother's already been…exciting you before you even got to me." The witch lifted long enough to rip open his jeans and tug them down enough to release his cock into the night air. She whistled hungrily between her teeth as she looked at it and then wrapped a hand around him, squeezing tightly until he grunted with the feeling. "Or was it watching me that did it? Hmm? Did you wish you were part of the fun?"

Dean could do nothing but watch as she rose over him and then slid down onto his cock, taking him inside her with a long, guttural moan. "No! SAM!" Dean shouted it while his skin crawled with disgust. "You sick, twisted bitch!" He closed his eyes, refusing to look at her as she rode him and his body betrayed him with little shocks of pleasure.

She rode him hard, slapping her hips into his, twisting on each down stroke. She tore at his shirt, trying to reveal skin as she began muttered an incantation in broken pants of breath. "Going to make you…one of mine…and you'll like it." She moaned again as she took him deeper inside her. "I promise you'll like it."

"Fuck you!" Dean yelled and wanted to rip her to pieces with his bare hands. His eyes shot open at the sound of a growl screamed from behind her and he knew; Sam had realized what was happening. "Lady, you are so dead…" He yelled angrily as her hand came down to touch his head and darkness took him, leaving only a glimpse of his brother slamming into her and rolling them both away.

Sam emptied his clip into the leopards circling him and looked up. The sight that met him froze his blood in his veins. The witch straddled Dean's lap, grinding down on his cock. He and the cat in his mind both shuddered with rage. A silent litany of 'mine-mine-mine' went through his head and the scream that broke loose of his throat had very little human about it. He let the rage take him over and sprinted toward them. He saw the witch touch Dean's head, and then Sam tackled her off him and rolled away through the pine needles with her.

"Bitch!" Sam snarled it at her and let the cat in his head have free reign as he pinned the struggling woman under him. He felt her tense under him, and a coil of power begin to build around him and Sam lunged down, taking her throat in his teeth. He growled as her blood flooded his mouth and gave himself over to the urge to rip and tear. Sam growled again, frustrated that his teeth didn't seem sharp enough to easily do what he wanted while she thrashed under him, but he put his back into it, clenching his teeth around her windpipe and tore his head to the side. The sound should have sickened him even as the witch's scream abruptly cut off, but it didn't. He spit the chunk of flesh off to the side and looked back down at her while her blood ran down his chin and neck.

Sam watched the light fade from her eyes and jerked his head up with a snarl as he sensed more of the leopards circling. "No!" It was a guttural cry as he staggered to his feet and ran back to Dean. He dropped to his hands and knees over him and growled at the circling cats, letting them know Dean was his, his territory, his property, his…mate. For just a moment, Sam's mind reasserted itself just enough to wish he could change for real and not be trapped in his clumsy, human body. He opened his mouth and bared his bloody teeth at the nearest of the leopards.

Sam twitched in surprise as the remaining dozen or so leopards began to scream in unison. He watched them drop to the ground and writhe in some sort of agony and then each cat seemed to burst apart in a shower of red, leaving a dozen men lying unconscious on the ground. "Whoa," Sam breathed. He looked down and dropped his head to his brother's forehead, breathing heavily as he slowly took back control from the animal in his mind.

"Dean," Sam whispered against his lips and cradled his face in his hands before he leaned back to look at him, but he was still unconscious from whatever the witch had done. He could see the pulse jumping in his throat and took comfort in that. Sam leaned down, thinking to kiss him, and then the taste in his mouth came blisteringly clear. "God…oh…oh, god!" He scrambled back off his brother and away, wiping furiously at his face before he turned and retched blood into the pine needles. He coughed as the sickness eased and sat back, wiping his face again and studiously didn't look over at the body of the witch. Along with the nausea, came the pain from the myriad claw marks he'd suffered in his fight with the other leopards. Sam pushed it aside. He needed to get Dean to safety and far away from this place.

He crawled back to his brother and gently tucked him back into his pants, promising to clean his brother as soon as they got back. "I've got you, Dean," Sam said in a voice gone hoarse with self-disgust. He pulled Dean's arms until he was sitting and tipped him up over his shoulders in a fireman's carry. Sam staggered to his feet, took a last look at the dead witch and the sleeping men and left. The smell in the clearing was threatening to make him vomit again. and the taste of her blood was still far too strong in his mouth.

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Sam parked the Impala in front of their motel room and unclenched his fingers from the wheel with a stuttering breath. He glanced over at Dean, still asleep in the passenger seat, and made himself climb out and go around the car. He was still reeling from what he'd done to the witch. It wasn't killing her that made his legs want to crumple and his eyes burn; it was the way he'd done it and that he could still taste her in his mouth that made him want to crawl into a corner somewhere and never come out. He opened the passenger door and knelt down to pull Dean out and slide him over his shoulders again.

"Almost there." Sam muttered, more for his own benefit than Dean's. He was having a silent little freak-out that his big brother wasn't able to poke at him or tease him or damn well hold him and tell him it was alright…what he'd done. He briefly considered calling Bobby and then realized he didn't even want to begin to try and explain what was happening to him…to them. Sam opened the door, kicked it shut and laid Dean out on his bed. He set quietly about the task of divesting his brother of his clothes as gently as possible and smirked for a moment as he lifted his big brother in his arms. Dean would slap him if he caught Sam carrying him like some blushing bride into the shower.

The smile fell away as Sam remembered why he felt the need to clean his brother and had yet to burn away the image of the witch…raping Dean…from his mind. He choked back a sob as he stepped into the hot spray and let Dean's legs slowly drop until he was supporting him with an arm around his back. Sam looked down at Dean's face and suffered a little because his big brother was never supposed to look this…helpless.

Sam washed Dean awkwardly, unwilling to set him down or leave him. He had a hard moment, fighting the need to throw up yet again when he took a mouthful of water from the shower spray and spat blood-pink water into the drain. He wanted to brush his teeth but Dean needed him first. He turned off the water and grabbed a towel, draping it over Dean's back as he picked his legs back up and carried him out to the bed. Sam laid him down and dried him half-heartedly before lying beside him and wrapping an arm around Dean's waist as he nudged his head under his brother's chin in a tacit plea for comfort the older man couldn't give.

"Really wish you'd wake the hell up, Dean." Sam said softly into his chest. He swallowed and once again tasted blood. "Ugh…god." He gagged and scrambled off the bed and back into the bathroom. Sam vomited into the toilet and the nausea cramped his stomach hard enough to double him over and take him to his knees when a small chunk of the witch's flesh came up. His back arched with the need to get the taste of her out of him and he startled badly when he felt a familiar hand on the back of his neck.

"Easy, buddy." Dean soothed and knelt next to him. He'd woken, surprisingly, in bed and naked with the sound of Sam retching filling the room. He squeezed the back of Sam's neck when he heard a choked sob. "Take it easy, Sammy. I'm right here. I gotcha."

Sam let the sound of Dean's voice soothe him and the heaves finally died away. He slumped back into Dean's waiting arm. "Dean."

"Hey. Hey. Right here. Breathe, Sammy." Dean looked on in concern at Sam's pale face. "What the hell happened?"

Sam shook his head and stood with Dean's help. He went to the sink and grabbed his toothbrush. "Witch is dead." He loaded his brush with toothpaste and started brushing his teeth while Dean watched with a confused look on his face.

Dean gave his brother the time he seemed to need, unashamedly standing there naked and it never occurred to him to get dressed, not with that bloodless, kicked-puppy look on Sam's face and the obviously untreated claw marks on his lower back, stomach, and right thigh. Something bad had happened and he was going to find out what it was. Once Sam was done spitting clean water into the sink, Dean reached over and turned the faucet off then took Sam's shoulders and steered him out. "Sit." Dean ordered and pushed him down on the end of the nearest bed. He knelt in front of him and looked into tortured blue-green eyes.

"Ok, talk to me, Sam, 'cause I remember what that bitch was doin' to me, but why are you..." Dean stopped and shook his head. "What happened that I missed?"

"I killed her," Sam said softly and stared at a point over Dean's shoulder.

"Yeah, I get that. What's the problem?" Dean shrugged. "She needed killing. That was the plan."

"You don't understand. I killed her. I…I fucking killed her!" Sam shot up from the bed, suddenly unwilling to sit there with Dean's patient, understanding gaze on him. Anxiety rushed through him and made him tremble as he turned back to his brother. "I tore out…her throat…with my teeth!" Sam screamed it as it all suddenly became too much for him. "It wasn't…I…wasn't human, Dean!"

"Shit," Dean breathed as he watched Sam's chest heave with distress. He shook his head the moment he heard a growl escape his brother's lips. "No. Uh uh. Stay with me, Sammy." Dean went to him and grabbed his brother's shoulders in a vice-like grip. "Sam! Look at me!" He waited until Sam focused on him though he trembled under his hands and breathed like he'd run a marathon. "There's not a damn thing wrong with what you did." Sam was shaking his head and Dean rode over him. "You did what you had to do, and I don't give a damn how you did it!"

"I ripped out her throat!" Sam shouted again as guilt and fear burned through him, even as the leopard in his mind stretched its influence again. He tried to jerk out of Dean's grasp, but his brother held firm. "You have to…I can't…Dean?"

"Shut up!" Dean said fiercely knowing damn well Sam was working up to asking Dean to kill him for being a monster. "Don't even think it! You hear me?" He gave Sam a shake and dragged him to the nearest bed. He shoved Sam down on it. "Sit still while I check these out." He flicked a finger at one of the claw marks on Sam's thigh and nodded when the small shock of pain seemed to bring Sam back to himself a little. He went to his bag and pulled the first aid kit out then sat behind Sam. "Just breathe and shut up for a minute."

Sam stared at the floor and focused all his energy on not letting the thing in his mind take over again. He flinched with each touch of antiseptic on the wounds on his back, surprised that he hadn't even really noticed they were there.

Dean taped a bandage over the wounds and moved around to Sam's front. He appraised Sam's mental state, studying his face, and shook his head. Sam was still on the edge of hysterics, and he supposed he couldn't blame him. Killing was nothing new to either of them but using your own teeth to tear out a throat…Dean shuddered for a moment with a visceral memory from his time in Hell when he'd been on the receiving end of that little gem.

"Take a breath, Sam," Dean urged softly, noting that he hadn't heard Sam breathe in more than a minute, and his little brother listened, taking in a harsh breath and letting it out while his hands clenched and unclenched in the sheets at his sides. Dean sighed. He could feel the energy practically vibrating through his brother, and it was only a matter of time before Sam, or the thing inside him, had another manic moment. Dean reached down into his bag and felt around, finding what he wanted and looked back up.

"Sammy. Trust me?" Dean asked earnestly.

Sam forced himself to meet Dean's eyes, swallowing hard around the growl trying to work its way out of him again and nodded. He didn't trust himself to speak.

"Ok." Dean picked up Sam's legs and put them on the bed. "Lay down." He rightly assumed Sam's tenuous control was keeping him silent and worked around it. "Give me your arms." When Sam looked up at him without moving, Dean grabbed his right arm and pulled it up to the headboard. He quickly whipped up the cuffs he'd taken from the bag and snapped one ring around the wrist while Sam's eyes widened and that feral look started to crawl into his eyes. "Gimme the other one. Now. Sam!"

Sam fought the creature in his mind that was now pacing angrily, warily, at Dean's order. He raised his left arm and let Dean cuff him to the headboard. This time he couldn't stop the growl from burbling out into the air.

"Easy, Sammy." Dean sat next to his hip and grabbed the antiseptic again. "Just didn't want you takin' off on me while I'm cleaning your wounds." Dean efficiently cleaned the claw marks on his brother's chest, bandaging them quickly and figured from the way Sam's body was starting to twitch in the restraints, he was on borrowed time until he'd have to distract the damn cat and put Sam back in the driver's seat. Dean moved and straddled Sam's legs below his knees and bent to care for the claw marks high on his thigh.

Sam's breath was coming harshly through his nose as he watched Dean and felt his fingers moving carefully on his thigh. Inside, he was still fighting the need to run or worse…kill, but Dean naked, over him, his hands moving surely over his skin let Sam back into himself enough to know that he could turn what the leopard was feeling into something more constructive. "Dean."

Dean looked up in relief as Sam spoke his name softly. He smiled and finished taping the bandage in place, tossed the first-aid kit over the side of the bed and then moved to sit higher on his brother's hips. "Right here, Sammy." Dean put sure hands around Sam's face and leaned down to take his lips, tilting his brother's head up. He licked along the seam of Sam's lips and thrust his tongue inside hungrily when Sam opened them with a soft, sobbed moan.

"Need your help, Sammy." Dean said huskily into his brother's mouth, needing to make sure Sam's attention was completely focused on him. "I can still see her. I can still…feel her on me. You gotta make me forget, Sam." It wasn't a total lie. Dean could still feel her and the helplessness he'd experienced was eating at him. She'd taken something from him and he knew losing himself in Sam would bring it back. "You're mine, Sammy." Dean bit gently at his brother's jaw and down to his neck below his ear. "I'm yours, little brother. Always."

Sam shivered under him with those words and arched his chest up into Dean's as his brother's teeth bit harshly into his neck. "Mine." Sam gasped and closed his eyes. He pulled his arms in the cuffs, wanting to touch and snarled when he couldn't.

"Uh uh." Dean leaned up and grinned down at him mischievously. "This is my show and you're gonna take whatever I give you."

Sam shuddered in anticipation at the heated look in his brother's eyes and, thanks to Dean's presence, didn't panic when the purr rumbled out of his chest unbidden as Dean's hands smoothed down his chest, careful of the bandage.

"That's my boy," Dean murmured happily and bent to mouth at the column of Sam's neck again. He grazed his teeth over Sam's throat and then went back to kissing him, wanting to be sure Sam wouldn't think he was avoiding his mouth because of what he'd done to the witch. He licked along his teeth, the roof of his mouth and sucked Sam's tongue into his mouth before releasing it and biting his bottom lip. All the while, Sam made helpless, needy noises into his mouth, and Dean groaned as his cock filled just listening to them.

"Shit, Sammy." Dean laughed, a little breathless, and slid down Sam's body a little more to drop his hips between his legs. "Do you know how fuckin' sexy you are? Just those damn noises…holy crap."

Sam smiled and sucked in a breath when Dean thrust his hard cock against his. He rolled his hips to meet Dean's hungrily and let loose a loud moan as his brother sucked on one of his nipples and caught it between his teeth. "Dean!"

Dean smiled and moved to give the other nipple the same treatment until Sam was a gasping wreck with his head thrown back and arms hanging limp in the cuffs. He considered letting Sam go and then decided he liked the idea of taking him completely apart while Sam could do nothing but enjoy it. Sam who had saved his life and carried him out of that damn forest, bathed him and protected him and had nearly drowned under the weight of thinking he was a monster. Dean gave his own growl and slid down until Sam's cock was in front of his face.

Sam felt Dean's breath on his dick and looked up in time to watch him swallow the head into his mouth. He threw his head back on a short cry that became a drawn-out moan of pleasure as Dean took him deeper, tongue pressing along the underside of the shaft. His hands being locked above him both frustrated him and sent a dark little thrill of pleasure through him. Neither he, nor the cat inside him suddenly minded being at Dean's mercy. In fact, as Dean dug his tongue into the head of Sam's cock and made him writhe with pleasure, he decided he pretty well fucking loved it.

Dean made himself stop sucking Sam's cock, addictive as it was because he little brother was practically whining above him while the cuffs jingled against the bed frame ever so often. He leaned up and plucked the bottle of lotion from the nightstand and crawled up Sam, straddling one leg to lie half on top of him as he coated the fingers of his hand and slid them down. Dean stroked his slick hand along Sam's dick until his brother cried out and smiled as he released him and pushed his fingers behind Sam's balls and to the hole he was planning on pounding into the mattress very soon.

"Love you, Sammy." Dean breathed as he bent and kissed him again and then slid two fingers into Sam. He groaned when Sam's back arched beautifully again. "So hot, little brother." Dean leaned back enough to watch as he worked his fingers into his brother and crooked them, finding the little bundle of nerves that made Sam shout and gasp. He hit it again and then again, thrusting his fingers into him like it was his cock and brushed his sweet-spot each time until finally he got what he wanted; Sam was back in control enough to beg as the purr slowed slightly.

"Please…please, Dean. God….need you in me…fuck, Dean…please!" Sam begged shamelessly. Dean's fingers were driving him so close but without any friction on his cock, he couldn't slide over the edge which was, of course, exactly how Dean wanted him as he opened his eyes enough to see the hungry, satisfied expression on his brother's face.

Dean hummed and pulled his fingers from Sam, slicked his own cock and moved to kneel between his legs. "I wanna hear you scream my name again, Sammy." Dean said in a low, gravelly voice that actually made Sam moan and his cock twitch as he watched. "So fuckin' eager for me, aren't you?" Sam only moaned and Dean picked up Sam's unwounded leg, sliding it over a shoulder as he turned him slightly on his side. "I didn't hear you." Dean pressed the head of his cock to Sam's entrance and turned his head. He put his lips to the back of his brother's knee and bit.

Sam cried out, jerking on the bed as Dean bit and sucked the sensitive skin behind his knee. "Fuck! Yes, yes! God, Dean…please. Please!" He was close to crying with how overwhelming it was and then Dean thrust into him in one long, slick slide and Sam did scream. Turned on his side with one leg over his brother's shoulder, his mouth working behind his knee and his cock slamming into his sweet-spot…Sam was completely lost in the sensations and cried out again as Dean worked his thick cock out of him and slammed back in.

Dean groaned loudly into Sam's knee. His brother was going to have the mother of all hickeys behind his knee when Dean was done but the way Sam was simply losing it on the bed was worth it. Dean braced a hand at the bend of Sam's hip on his upraised leg and used it to pull him in hard, skin slapping skin and Dean turned his mouth from Sam's knee finally to suck in a breath and grunt and moan with the feeling of Sam's muscles tightening around him. "Fuck, Sammy!" He was quickly losing it amidst the delicious, broken sounds Sam was making, his body trembling and his hands cuffed to the bed. "Son of a…come for me, little brother!" Dean took his brother's cock in his free hand and squeezed as he stroked up roughly in time with his thrusts.

Sam shouted and felt tears escaping his eyes from the sheer, unbelievable pleasure and conflicting sensations; His hands cuffed to the headboard and immobile, Dean's hand on his dick, Dean's mouth once more sucking hard behind his knee and Dean's cock sliding inside him to pound relentlessly at his prostate. "Fu...fuck…Dean….holy….DEAN!" Sam screamed it as his cock pulsed hard just the right side of pain and he came.

Dean watched Sam's cock spurt onto the sheet again and again while Sam had what looked like a pleasure driven seizure and screamed it out with his hands twisting in the cuffs. He bit one more time, hard behind Sam's knee as he shoved roughly inside him and earned another, smaller orgasm as his own crashed into him. Dean shouted, throwing his head back as his hips stuttered and slapped into Sam a few more times while he came hard enough to white out his vision. "Fuck…holy…fuckin' hell." Dean gasped and let Sam's leg fall from his shoulder. "Sammy?" Dean called, but his little brother had, literally, been fucked into unconsciousness.

Dean chuckled, breathless with exertion and slipped out of his brother. He leaned over the side of the bed and got the key from his bag before crawling up and freeing Sam's hands to drop boneless to the bed beside him. He pulled Sam into him, rolling his brother half onto his chest and tucked Sam's shaggy head under his chin. Dean rubbed a hand softly up and down his back, avoiding the bandaged claw marks and chuckled softly when he felt Sam stirring finally.

"Hey, Sammy." Dean curved his free hand around Sam's face, tilting his head to get a look as his eyes fluttered open. "You alright now?"

Sam stared at him for a moment while his eyes uncrossed and then smiled. "Yeah." His voice was hoarse and he rolled his head back under his brother's chin, listening to his heart thumping comfortingly under his ear. "Dean…thanks." He didn't mean for the sex…or not just for the sex. Sam smirked. He meant for talking him down, for helping him take control again and understand that what he'd done didn't make him a monster. He'd done what he had to to save Dean, and just as Dean had said, there was no line he wouldn't cross to do that. He pressed flush against Dean from neck to hip as the purr vibrated out of his chest again, this time from contentment, and felt the leopard in his head yawn with satisfaction and settle back into his subconscious.

"Hmmm." Dean hummed and held his hand over his brother's back, pulling him closer. "I can get used to my own personal magic fingers."

Sam snorted a laugh but didn't have the energy to hit him. He shifted his head, rolling it until he had his nose under Dean's ear and breathed in the scent of him. It steadied him and excited him at the same time and if he didn't feel like walking was beyond him, he'd have turned the cuffs on Dean. It would have to wait. Sam smiled and purred breathily into his brother's ear. "Next time, I'm tying you up."

Dean shivered and grinned, wrapping both arms around Sam as his little brother slipped into sleep. "Have to catch me first, Sammy." He chuckled and figured that would be a fun wrestling match. Dean wondered if he could lure Sam into a vat of jello somewhere for that one and drifted to sleep with that image dancing merrily in his head as he reassured himself; Sam wasn't normal. Neither was he. There wasn't much point in worrying about it unless they had to, so he wouldn't borrow trouble. They weren't normal, but they were alright and they were Winchesters, dammit. They'd survive this little change.

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The End.