Title: Shifting the Boundaries

Author: Wincesteriffic Kaz

Info: A shapeshifter with a taste for Sam starts a curse that changes everything. Dean/Sam

Author's Note: This first time Wincest is something of a gift for my friend who got me into writing it in the first place, bless her evil little heart. This one's for you, Pimp momma fly. :P …I'm her Wincest Ho. It's a thing. XD

Graphic depictions within.

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

~Reviews are Love~

-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-0-

Sam groaned and pulled at the ropes binding his hands above his head. Dean was going to kill him when he found him. Sam looked up and felt his stomach clench…the real Dean would kill him – if his captor didn't take care of that first. This thing wearing his brother's face…this was not Dean. They had come to town on this job expecting a ghoul and instead had found a shifter. Sam rolled his eyes at himself. They found him the hard way. The son of a bitch had taken them both by surprise at the motel using the desk clerk's body. Sam remembered something sharp in his neck and then Dean falling to his knees beside him.

"Where's my brother?" Sam asked, watching the shifter's back where he stood at a small table.

"Motel," The shifter said and shrugged. "Wasn't interested in him." He turned and aimed one of Dean's broad grins over his shoulder. "Gotta say, I am enjoying being in his head though." He turned and walked over to Sam. "You ever wonder what he thinks about you?" Not-Dean trailed a hand down Sam's chest, watching him jerk away with a smile. "Your big brother's got some…less than pure desires where you're concerned."

"Shut up!" Sam shouted angrily. "Get off me!"

"And what I gotta ask myself, Sam…Sammy…" The shifter slid a hand under the shirt at Sam's waist and whistled at the feel of the chiseled muscles quivering under his hand. "…is just how long you've been carryin' the same damn torch for him." He smoothed his fingers along Sam's abdomen appreciatively. "You know why he does every woman in sight? It's to try and wipe out the image of you he has in his head." He leaned up and breathed it into Sam's ear. "You…naked…straining underneath him. Big bro's got some pretty kinky thoughts goin', dude."

"Stop," Sam growled at him as his brother's green eyes looked heatedly up into his own. "You're lying." He jerked at the ropes. "Why'd you take me?"

Shifter-Dean chuckled and reached up to Sam's head. He wrapped a few of Sam's hairs around his finger and tugged them free before stepping away. "I don't kill all my marks, Sam." He went back to the table and the various jars and bowls there. "It's not always about the killing. Sometimes it's just about having a good time." He laughed at Sam's snarl. "You and I are gonna have a very good time and you're gonna do everything I ask."

"Like hell!" Sam shouted, suddenly feeling distinctly uncomfortable as the implications began to come clear for him.

"I'll even keep your brother's face on for you." Not-Dean turned and gave him another long look. "You'll enjoy that. You know you will."

"You sick son of a bitch!" Sam struggled with renewed purpose while a tiny corner of his mind sat in stunned disbelief that his brother might actually feel the same way he did. He shoved those thoughts aside and pulled harder feeling blood begin to seep down his arms from his wrists. "You untie me and I'm gonna kill you."

"Oh, no, you won't." The shifter chuckled. "See, this is a little curse I picked up a while back from this…REALLY ugly witch in Mexico. Man, she was fugly and had to come up with a way to get her, uh…lovers…to cooperate." He laughed and moved aside so Sam could see the bowl he was working in. He let the hair he'd taken from Sam drop into the bowl. "Once I finish this, you'll be bound. All I have to do is touch you and you'll have six hours to…" He smiled and tilted his head, the gesture so very Dean it squeezed Sam's heart. "…well, not to be crass but, six hours to have sex with me or die." He snorted and turned back. "Trust me, you don't wanna let the six hours run out, Sammy. I've seen it happen. It ain't pretty or peaceful. They go screaming."

"Stop calling me that." Sam growled and felt panic begin to sweep through him. This was bad…very bad.

"Now, Sam. I could buy you a drink first if that'd make you feel better." Shifter-Dean looked at him and licked his lips. "There's nothing better than making a strong man submit, Sam. Call it a personal kink. It's why I took you and not Dean, although, I might go back for him wearing you." He seemed to take a moment and consider it, eyes glistening hungrily. "You know, I think I will." He laughed and lit a match, then let it fall into the bowl. There was a flash of light and a cloud of smoke. "You first."

Sam watched the smoke rise up and begin to snake across the room toward him. "No. No way." Sam pulled with all his strength at the ropes, chest heaving in fear as the smoke arrowed toward him. It slammed into his chest, dissipated, and left him gasping for air while the room spun.

"Time to play," Shifter-Dean said softly and started toward him, stretching out a hand and licked his lips.

Sam struggled to stay conscious and get his head up. He had to get free. He heard the shifter speaking, his voice getting closer, and then there was a crash and gunshots. Sam managed to pull his eyes open in time to watch his real brother burst into the room and shoot the creature dead. He couldn't help but marvel that this was the second time he'd had to watch this, and then Dean was coming for him. Dean was calling his name and stretching his hands out…

"No, No, Dean! No!" Sam yelled hoarsely, fighting the ropes in an attempt to stop his brother touching him before it was too late.

"Whoa! Whoa, Sammy! It's me. I mean, real me!" Dean shook his head at him, poor kid was so confused he still hadn't realized the shifter was dead. Dean reached up and put a hand on his little brother's neck…there was a flash of light, Sam crying out, and Dean was picking his head up off the floor. "Wha…"

"No, no, no. Oh, God." Sam was gasping once more as the curse blew through him, his back arching off the post he was tied to, and he knew they were screwed.

"Shit!" Dean pulled himself up off the floor and went to his brother. "Sam?" He reached up and started untying his hands. "What the hell was that?" He let Sam's arms drop and took his head, making him look at him. "You alright?"

"N…no, fuck." Sam shook his head and looked away.

"Ok. You gotta tell me what the hell's going on here." Dean stared at his brother's too wide eyes. "You look like someone just shot your dog. What is it?"

Sam looked down at his watch, wiping his own blood from the face and counted ahead six hours. "Can we just…go back to the motel? Please?"

Dean stared at him and didn't like the defeated tone of voice. He grabbed his brothers' arm. "Sam, what's wrong? Talk to me?" He'd gone through six kinds of hell when he'd come awake in the motel office and found him gone and the clerk's very dead body in the back room. Luckily for him, the shifter didn't know enough to turn off Sam's phone or the GPS signal.

"Motel. Please." Sam looked over at the shifter's dead body, still wearing Dean's face and shivered. "I'll tell you alright? Just…not here. Please."

Dean didn't like that Sam was almost begging and frankly, trembling under his hand on his arm. He sucked in a breath and nodded. "Alright. Come on."

Sam went along silently. His head buzzing in shock, knowing the conversation he was going to have to have with his brother. There was no escaping it, and his stomach started to churn with the tension.

-0-0-0-0-0-0-0-0-0-0-0-

Dean opened the motel room door and let Sam go in ahead of him where he vanished into the bathroom. He'd thrown up twice on the way back. "Hurry up, Sam! We gotta get outta Dodge and find a new motel, like, now!" He didn't want them to be there when someone eventually found the poor clerk.

"Sorry." Sam came back out of the bathroom and went to his bag, hastily shoving things inside and studiously didn't look at him.

Dean let Sam keep his silence while they packed and piled in the car. He figured whatever was wrong couldn't be life-ending or he would have told him already. He found them a motel twenty minutes away, let Sam obsessively unload the car, and then closed the door on the new room firmly. "Alright, Sam. Out with it. What the hell is so bad you don't wanna tell me?"

Sam froze in the act of sitting on the far bed and decided the bed was not where he wanted to be for this discussion. He raised his hands for patience while he tried to find the words. "Dean…"

"Shit." Dean cussed, getting a good look at his brother's bloody wrists. He waved a hand and went to his bag. "Keep talkin'." He pulled out the first aid kit, grabbed a chair and went over. He pushed Sam down to sit on the bed despite his resistance and glared at him. "Sam. Talk."

Sam nodded while Dean grabbed his right hand and started cleaning the rope abrasions. "The shifter, he…he…" He breathed through his nose, focusing on the pain in his wrists rather than his brother's face. "He cursed me."

Dean's hands jerked and he stared, shocked at Sam. "Say WHAT? You don't think maybe you should have mentioned this a damn hour ago? What kind of curse? How bad is it?"

"It's…" Sam shook his head. "That thing was seriously twisted, Dean."

"Shifter. Duh." Dean wrapped a bandage around his wrist and turned to the other. "What kind of curse, Sam?"

Sam glanced over to the clock beside the bed and closed his eyes. "I have five hours left, Dean."

Dean dropped his left arm and stared. "You wanna run that by me again? Five hours left until what?"

"Until I die, unless…." Sam swallowed. This was so much harder than he'd thought it would be. He wasn't sure he'd survive seeing the disgust on Dean's face that was about to be there. His brother didn't say anything. Dean just watched him; waiting. "Unless I have sex."

Dean blew out a breath. "Jesus, Sammy. Is that all?" He sat back and punched him in the arm. "Take me five minutes to find someone to clean your pipes for ya."

"No. Dean, wait." Sam grabbed his brother's arm and waited until he caught his eyes. "The curse was…specific. He…set the curse, and then he was going to…to touch me and that would set it off."

"And? He died." Dean's brows drew down in confusion and then rose again as shock overtook his face with the memory of what had happened when he'd first touched his brother in that room - the flare of light. "Wait…wait." He started shaking his head even as Sam began to nod. "No way." The implications ran round and round in his head; first, the sobering realization that the shifter had planned on raping his little brother, and that made him snarl with rage, but then…the even more mind-numbing thought that…he had touched Sam first. He'd touched his brother and activated the curse and now… "There has to be another way. Some way to break it. Something. I am not…I mean we can't…no fuckin' way."

Sam nodded and dropped his head. "I've…got five hours yet. I'll look."

"Five hours." Dean stood and started pacing, dragging his hands through his hair and not looking at his brother. "Jesus." Oh, there was a part of him that wasn't as disgusted as it should be; a quiet little voice he'd kept locked away in the back of his mind since Sam was a damn teenager. He snarled silently at that voice now because this was not going to happen; not like this. This…this was rape, and it wasn't going to happen. He heard Sam boot up his laptop and grabbed his jacket. "I'll be back."

Sam watched him go sadly. He didn't blame him escaping the room while he could and only hoped that whatever happened later…Dean wouldn't hate him for this.

-0-0-0-0-0-0-0-0-0-0-0-

Dean stood with his back pressed to the room door, staring at the beds as though they were somehow threatening hm. There was nothing. Sam had searched, made calls, done more searching, and even called Bobby coming up with a story about some other poor sucker being cursed, and even Bobby said what Sam had said a little while ago - get the guy laid or he's dead.

"This isn't happening," Dean said softly, angrily. He didn't want to accept that this was going to happen; that his little brother was even now in the bathroom…preparing himself. He shuddered and pushed himself off the door to pace furiously. "Son of a bitch," He growled it and only just stopped himself from putting a fist through the wall. Once he'd been forced to agree to this, Dean had offered to, well, be the girl, anything to spare his brother the pain, 'cause no way this wasn't gonna hurt, but Sam had shot him down with logic. The shifter had planned on being the one on top, and they couldn't risk that doing it the other way around would cost Sam his life. He caught himself smirking then, remembering Sam's uneasy joke that he didn't want to break Dean, him being bigger and all.

The bathroom door opened and Dean froze like a deer in headlights as Sam came hesitantly out in nothing but a pair of sweatpants. "Sammy…"

"We have to do this." Sam said firmly. "There's no other choice." He'd made his peace with this. They had to. He walked stiffly to the bed and sat, staring at the floor. "Dean. Please."

Dean growled a curse and dropped his head in resignation because, as hard as this was for him, it was going to be so much worse for Sam. "Fuck." He took his jacket off, throwing it and pulled his shirts off angrily. He braced a hand on the wall and kicked off his boots then looked uneasily over at Sam. "You know, you gotta…this…have to take it all off, Sam." He tried for humor, but it sounded more pained as he popped the fly on his jeans and tried to look anywhere but at his brother as he stripped and stood naked.

Sam nodded shakily. Seeing Dean naked out of the corner of his eye froze his breath in his lungs. It rocked him to his toes, and not just because of how screwed up the situation was but because, in a moment, he'd have all that lean, tanned muscle over top of him, and Sam realized with a dizzying rush, he wanted it. He made himself move, tugging his sweats off with shaking hands and kicking them to the floor.

Dean felt a sudden jolt of lust as he looked at his naked brother and saw that Sam's cock was half-hard and quickly filling. He swallowed noisily and decided he had to take control of this or Sam was going to die while they waffled around. "Ok, Sam." Dean went to him and touched his bare shoulder. "Lay down." He saw his brother's adam's apple bob as he nodded and pulled his legs up to lay awkwardly on his back. Dean took a steadying breath and crawled onto the bed until he was above his little brother, propped up on his arms and only barely touching him with a brush of their thighs against each other.

"I don't…" Dean started and stopped, choking on emotion as Sam practically vibrated with fear beneath him. How could he possibly do this to him?

"It's ok." Sam said it softly to try and calm the near panic he could suddenly see on his brother's face as he hovered over him. Dean's fear helped him swallow back his own.

"No, it isn't! Dammit, Sam!" Dean started to push up and away.

"Dean!" Sam grabbed his shoulders and pulled, staring up at him. "It's this or die." He waited for Dean's eyes to settle on his. "I don't wanna die, Dean, so…I'm ok with this. I mean it's….it's weird and…I don't know, but I'm ok with it."

Dean growled and looked away, anywhere but at his naked little brother underneath him and being so damn reasonable. "It's gonna hurt," He said finally, gruffly.

"I know." Sam closed his eyes for a moment and took a breath. "Just…can we do this?" He glanced over at the clock on the nightstand. "I've got less than two hours, Dean."

Dean sucked in a breath of his own and nodded, wondering how fucked up it made him that he was hard; hard because Sam was naked and trembling beneath him…and wanting, if his little brother's hard-on was anything to go by. He took every impure thought he'd ever had about Sam and shoved them away nice and deep. He needed to make sure Sam never knew because it was bad enough to finally get what he'd secretly wanted for so long, but like this…it was little more than rape, whether Sam saw that or not. Dean could see it clearly enough for both of them.

"Alright." Dean sank down, resting his weight on his brother and put his head in Sam's neck so he wouldn't have to look at Dean while he did this to him. He ruthlessly crushed the groan that tried to break out of him as Sam's knees bent up to bracket his hips; holding him in place. "Ready?" Dean asked softly and felt Sam nod, his long hair brushing the side of Dean's neck and making him shiver. Dean knew Sam had prepared himself as well as he knew how in the bathroom, but it was still a bit of a shock to feel the lube there as he reached between them and guided the head of his cock, pressing against the tight ring of muscle. "Ease up, Sammy," Dean's voice was a tight whisper of rigid control as he pressed forward. "Relax. Just...just try."

Sam nodded again and took a deep breath as he worked to relax himself and let Dean in. It wasn't as though he'd never thought about this before. He had ever since he was a teenager and gone from wishing he could look like his big brother to wishing he could wrap himself around him instead. Sam did that now; wrapping both arms around Dean's shoulders and across his back as the head of his cock slipped inside him and he gasped. "God!"

"Ok, Sammy?" Dean's voice was a breathy whisper as he resisted the urge to just slide home, knowing how much pain that would cause Sam, but, oh, God…the feeling of being inside him, his little brother, it stole his breath with need.

"Y…yeah. I'm…I'm ok. Keep going." Sam bit his lip at the sensation. It was too much, too big and he felt like he was being split in two and at the same time he wanted…needed more. A part of him suffered with the fear that Dean would hate him if he knew how long Sam had wanted this. Then, he remembered the things the shifter had said to him and a small flame of hope lit inside him. He grunted with the pain and had to concentrate then to relax and let him in.

"Easy," Dean instinctively brought a hand up to cup the side of Sam's face and offer comfort. He couldn't listen to him in pain and not do something and it was so much worse knowing he was the cause. Dean stilled, half-sheathed inside his brother and waited until he felt the muscles relax and then pressed forward again. "I've got you, Sammy."

Sam hooked his legs behind Dean's, needing the support as his brother bottomed out inside of him. He felt full to bursting and it was overwhelming. His body was fighting the need to push out the intrusion while his mind wanted more…now. Sam shifted his hips slightly and sucked in a surprised breath as the pain gave way to the first real pleasure.

"Sam?" Dean asked and felt his brother tilt his head back in his hand.

"Move," Sam breathed it into Dean's ear and felt the shudder that passed through his body. "Please, Dean. God…please, move!"

Dean shuddered at the raw need in his brother's voice and felt his world start to shift with the knowledge that Sam seemed to actually want this…want him. He slid his hand from Sam's face around the back of his neck and held on tightly as he pulled his hips back, sliding slowly out of Sam with a delicious drag of flesh on flesh that drew a moan from him he couldn't stop. He stopped until only the head of his cock was still inside and then pushed back in. He kept it slow, feeling Sam begin to stretch around him and felt the breath stuttering in his brother's chest.

"Dean," Sam moaned it as Dean filled him up again and started up a slow pace, in and out that was making his eyes cross with sensation. "Fuck…yes." He panted and arched up into Dean's chest, gasping anew as his neglected cock was pressed between them to rub against both their bellies. "Dean!"

"Shit, Sammy," Dean groaned his name and pushed up, needing to see his brother's face. He needed to see that was he was hearing was real; that he wasn't imagining it. He looked down at Sam's face as he threw his head back, jaw slack, panting for air and saw nothing but pleasure there. "Holy crap…Sam?"

Sam managed to open his eyes and looked up into Dean's surprised green eyes. He smiled and slid one hand up the back of Dean's head into his hair, giving a tug. "You think…you could maybe…pick up the pace, big brother?"

"Son of a bitch." Dean whispered it like an oath and stared down at his brother. Sam really did want him. That thought sucked away all the fear and doubt and left him gasping. He dropped his head to Sam's and brushed his lips against his brothers' as if asking permission, needing it…and Sam opened to him without reservation. Dean groaned loud and long and thrust his tongue into Sam's mouth as he thrust his hips forward and sheathed himself deep inside him; swallowing the startled cry of pleasure between them along with his own.

Dean was lost in the feeling as his hips slapped into Sam's with each thrust. His brother's moans and the needy little gasps were like fuel to a fire and drove him and Dean decided he needed to find out if he could make Sam louder. He grinned into the kiss they had yet to break and dropped his hips down, changing the angle and then shoved back inside.

Sam cried out, throwing his head back as Dean hit something inside him that set off lights behind his eyes. "Oh, my go…do that again!"

Dean chuckled breathlessly and bit along his brother's jaw as he thrust inside him again and earned another pleasure-filled shout. "Fuck, Sammy," He groaned into his neck. He was so close already and could feel Sam trembling beneath him with every thrust and his painfully hard cock trapped between them.

Sam never wanted this feeling to end. Dean driving in and out of him, his brother's hand warm as it squeezed the back of his neck, those sinful lips of his pressed to Sam's as he licked inside Dean's mouth and tasted him with abandon because, finally, he could. He wrapped his legs over his big brother's hips and shouted when Dean reached between them suddenly to wrap warm fingers around his aching cock. "Fuck!" It was too much. Who but Dean could possibly know to give that little twist at the top of each stroke of his hand, timing it at the same moment he slammed home inside him and hit that bundle of nerves again and again.

"Dean! Dean, I'm gonna…oh, g-god!" Sam thrashed his head, unable to hold back as a tidal wave of pleasure blew through him.

Dean felt Sam's cock jerk in his hand and he leaned up further to give himself more room. He let go of Sam's neck and thrust his hand down, picking up one of Sam's legs and sharpening the angle of his thrust even more as his own breath clogged in his throat. Sam came with something close to a scream as his back arched off the bed. His nails bit into Dean's back with little bites of pain-pleasure and Dean was lost watching him as his own orgasm crashed into him. He shouted it to the ceiling while Sam's cock pulsed in his grip, shooting hot stripes of come up his chest and he buried his own as deep as he could go inside Sam while wave after wave of pleasure swamped him. Then, the curse broken, a bright flash of light erupted from them both and took the world away from him.

Dean came back to his senses to find he was sprawled on top of Sam with his face buried in his neck. He moved grudgingly, picking himself up and brought a hand up to palm the side of his brother's face. "Sammy?" His voice was hoarse and Dean looked over to the clock and back down. "Sam?"

Sam blinked lazily and looked up at Dean's concerned face. He could still feel his brother's softening cock inside him and the sticky mess between their chests and…he didn't damn well care. A slow smile spread across his face. "Hey."

Dean blew out a breath in relief and dropped his forehead to Sam's with a breathless laugh. "Hey yourself." He leaned back up to look at him. "You uh…you ok?"

Sam nodded and glanced over at the clock. "Still alive." He threaded his arms under Dean's and around his back when his brother started to pull away. "No. Stay."

"Sam…" Dean started but Sam shook his head and pulled him in tight.

"Don't." Sam was overcome with a sudden fear that Dean would get out of the bed and things would never be right between them again. There was only one way to make sure that didn't happen. He tucked his head under his brother's chin so he didn't have to look at him while he said it. "Dean…I wanted this." He took a steadying breath. "I've wanted this…you, for so long. That shifter, he said a lot of crap, but he was right about that…about how I f-feel…about you."

Dean felt him trembling under him again and knew this time it had nothing to do with feeling good. He sighed and settled his weight into his brother again. "Sam…I was just gonna grab your shirt off the floor and clean us off. I wasn't going anywhere, you big girl."

Sam dropped his head back to the pillow and looked back up at him with a frown. "You weren't?

Dean ducked his own head for a moment before meeting his eyes again. "That shifter, he used my face for a reason, didn't he?" He saw his brother's eyes widen and nodded. "He told you." Sam nodded in return and Dean sighed. "You were never supposed to know, dude." He leaned over the side of the bed and grabbed one of Sam's shirts before sliding off him to the other side of the bed. "You friggin' hero-worshipped me, you know?" He wiped off Sam's stomach gently and then his own. "I couldn't…I mean, if I'd ever…I'd never have known you weren't doing what I wanted just 'cause of that."

Sam grabbed the shirt from him and tossed it aside before tackling his big brother into the bed and pinning him. "Did it ever occur to you that I have a mind of my own and maybe you should have just fucking asked?" He glared down at Dean's sheepish grin. "Jesus, Dean. Half the reason I didn't stay in touch with you at college is because I thought there was something wrong with me and…and you'd hate me!" Sam rolled back off of him and started to get out of the bed.

"Dude!" Dean grabbed his brother and pulled Sam's back in against his chest, wrapping a leg over his hips and kept him firmly in place. "You can be pretty damn stupid for a genius, you know that? You realize I never said anything to you for the same reason?" He rolled his eyes for the massive chick flick he was finding himself in the middle of but knew it had to be done. Dean put his head near Sam's ear. "You think there's any part of me that could survive it if my little brother hated me? If he thought I was a freak for…for wanting him? Like this?"

Sam closed his eyes and relaxed. Dean was right. He settled into the warmth of Dean's chest with his arms around him and nodded. "Ok." He felt the tension leave his brother's body and Dean's leg settled heavier on his legs. "You are a freak, though." He snorted when Dean bit his ear and growled at him.

"You're the bigger freak." Dean reached behind him and yanked the blanket over them both with a satisfied smile. "Now can we please get some damn sleep? Some of us had quite the workout."

Sam snorted and pushed back, not minding at all that he'd ended up the little spoon somehow. "Might have to work on your definition of a workout."

"Are you kiddin' me right now?" Dean leaned up and slapped a hand into his brother's bare ass with a crack, grinning when he yelped. "You think your ass is sore now, buddy…"

Sam laughed. He couldn't help it. His ass was sore and he probably wouldn't be sitting straight for a couple days, but it was a good sort of sore, a comfortable sore that said they weren't hiding anymore…that he didn't have to hide anymore. He gave in and snuggled back into his brother's chest and pulled his arm back over top of him.

Dean groaned and rolled his eyes. "Well, that's an effective way to end an argument." He chuckled and settled back behind Sam under the blanket. "We're not done with this discussion."

"Mmm hmm." Sam smiled and closed his eyes, content.

Dean turned his face into his brother's hair, breathing in the scent of him and let it settle his world into its new place. If the shifter hadn't earned death a hundred times over, he'd have sent the son of a bitch a fruit basket for giving him this; giving him Sam. He tightened his arms around his little brother and breathed deeply in contentment as both their breaths evened out into sleep; wrapped around each other.

-0-0-0-0-0-0-0-0-0-0-0-

The End.