Posted originally on the Archive_of_Our_Own at https://archiveofourown.org/
works/4293501.
  Rating:
      Explicit
  Archive Warning:
      Underage
  Category:
      M/M
  Fandom:
      Supernatural, Wincest_-_Fandom
  Relationship:
      Dean_Winchester/Sam_Winchester
  Character:
      Dean_Winchester, Sam_Winchester
  Additional Tags:
      Wincest_-_Freeform, Weecest, ageswap, Teen!Dean, teen!Sam, top!dean,
      Bottom!Sam, Alpha!Dean, omega!Sam, Self_Lubrication, Knotting, Heat
      Cycles, Rimming, Tumblr_Prompt
  Series:
      Part 1 of A_Curse_and_A_Blessing
  Stats:
      Published: 2015-07-08 Words: 3190
****** If You Love Something, Set it Free ******
by WevyrDove
Summary
     Sam is the eldest son, but he is also an omega and a disappointment
     to his father. When his younger brother Dean presents as an alpha,
     Sam struggles with conflicting emotions. The ultimate test for the
     two brothers comes when Sam goes into heat during their usual summer
     family trip to the lake.
     Based on this prompt I received on tumblr:
     Could you write age swap wincest with teenager top alpha!Dean?
It was awkward for Sam when they found out Dean was an alpha; Sam was the older
brother, but he was also an omega. He had always been a disappointment for
their alpha father. So when Dean manifested as an alpha, Sam felt both relief
and despair. He was relieved that Dean would be able to carry on the Winchester
alpha line; at the same time he felt even more ashamed of his omega nature.
They were at the family cabin by the lake, where they spent every summer. Sam
thought back to last summer, when Dean was thirteen, before his brother had
shown himself to be an alpha. Sam knew those carefree days of swimming and
sharing a tent on the shore where probably going to end now. Although John
hadn’t said anything yet, Sam knew their father was keeping a watchful eye on
them both. He would probably send Sam away when he went into heat, so he
wouldn’t tempt Dean. Sam was expecting another cycle in a few days. He was
fairly regular, and he had already had some of the telltale signs of the
approaching heat. He was already anxious; it would be his first heat since Dean
had presented as an alpha.
“Hey Sammy!” Dean said cheerfully, coming up to where Sam was sitting on the
dock with his feet dangling in the water. He plopped down beside his brother
and removed his shoes and socks, placing his feet in the water next to Sam’s.
“Hey Dean.” Sam replied, his voice strained. His sense of smell always became
keener around the time of his heat, and Dean smelled amazing to him. His
brother’s new alpha scent was earthy, it reminded Sam of a cross between fresh
mown grass and petrichor. Sam bit his lip when Dean nudged his foot with his
own under the surface of the water. Dean was oblivious to his brother’s
discomfort.
“You wanna go swimming?” Dean asked carelessly. He was already wearing his
swimming trunks, with a tank top over his top half. Dean had grown so much in
the last few months his arms were thicker and more defined, his chest and
shoulders broader. He was catching up to Sam in height; only a few inches
separated them now when before Sam had towered over Dean.
“Nah.” Sam shrugged, even though he would have loved to slip into the cool
water. “You go ahead.”
Dean looked at him quizzically. “Suit yourself.” He slipped his tank top off
his head and dove into the water seamlessly. Sam watched his brother swim under
the surface for a minute, before popping up to breathe. He waved at Sam.
Sam waved back and sighed with frustration.
…
Sam was sitting and reading in one of the Adirondack chairs on the shore of the
lake when Dean came out of the water. Sam’s breath caught as he admired the
water sluicing off of Dean’s sleek body. His brother was only fourteen, but
alphas always looked older than they were, while omegas tended to be smaller.
Sam was eighteen; before Dean’s growth spurt and alpha presentation, it was
easy to tell who was younger and who was older. Now they appeared similar in
age.
“Water was great.” Dean grinned, water droplets still sliding down his body,
dripping from his hair. Sam grabbed the towel that was slung on the chair next
to him and threw it at Dean. “Thanks, Sam.”
Dean dried himself and then sat down next to Sam, still rubbing the towel
through his hair. “I’m starving. I wonder if Dad will barbeque tonight.”
Sam shrugged. “Maybe.”
Dean lay back and sighed with contentment. Sam looked over at his brother;
Dean’s eyes were closed so Sam could let his gaze trace the lines of his
brother’s body. He noted the trail of hair that started right below Dean’s
belly button and continued down into his swim trunks. Dean’s trunks had slipped
down past his waist and Sam could see the jut of his hipbones. Dean opened his
eyes and Sam turned back to his book quickly.
“I’m gonna miss you, Sammy.” Dean said softly. Sam put his book aside and
looked back at Dean. His brother was staring out at the lake. “I wish you
didn’t have to go to school so far away.”
“I’ll miss you too, Dean.” Sam replied. “I’ll visit, and I’ll still be home for
the summers.” Sam assured his brother. He waited for Dean to say something
more, but his brother stayed quiet.
A moment later, Dean got up. “Gonna get a snack. Want anything?”
“Nah, I’m good.” Sam said.
But he was anything but good. He couldn’t stop thinking about what was inside
Dean’s pants. It was a sure sign that his heat was on its way.
…
“Let’s camp out tonight.” Dean suggested, as they hung out around the fire,
toasting marshmallows. John had excused himself earlier and was already back in
the cabin.
“Uh.” Sam hedged. His mind was racing. He calculated that he probably had
another day or two before his heat took over. Still it was risky. His
marshmallow caught fire and Sam swore and blew it out. Dean laughed and Sam
glared at him.
“You can have mine, Sammy.” Dean said, offering his own marshmallow that was a
perfect golden brown.
“No that’s ok, Dean.” Sam declined.
“Aw, c’mon. I don’t mind the burnt ones.” Dean urged, still holding out the
stick with the marshmallow.
Sam offered Dean the burnt marshmallow. “Just have both. I’ll make a new one.”
“Thanks!” Dean grabbed it from Sam. Sam put on a fresh marshmallow on another
stick and started turning it above the fire again.
“You didn’t answer my question.” Dean said after a moment, looking at the fire
thoughtfully.
“What question?” Sam asked, feigning ignorance.
“Camping out? In the tent? Like we always do?” Dean reminded Sam.
“Oh, yeah.” Sam said. “Um. Sure.” Sam’s voice was steady when he replied, but
inside he was feeling reckless and his heart was pounding hard.
“Awesome.” Dean said. “It’s a good night for stars too.” Their tent had one of
those mesh window things on top so you could peek out at the sky without
worrying about bugs getting inside.
“Yeah. Awesome.” Sam agreed.
…
They were lying side by side in the tent; their sleeping bags open and laid out
underneath them. Sam already knew it was a mistake when they got inside the
tent together and he was surrounded by Dean’s smell. Inside the cabin, they
slept in bunks, so at least there was some separation. He should tell Dean that
he was feeling sick and that they would have to do this another time.
“I’m gonna miss this.” Dean murmured as they gazed upwards through the mesh
opening.
“Me too.” Sam replied.
They talked about previous summers they had spent at the lake, reminiscing
together; the fish they had caught (both of them exaggerating the size of the
largest catches), the time they had ran back in the cabin after they heard a
noise outside their tent (it had been the first time their father had let them
sleep outside by themselves), and that time they had gone skinny dipping in the
middle of the night and they had both scrambled to back to the shore screaming
(they had felt a large fish slip by their legs). They laughed together easily,
but Sam was hyperaware of Dean. He wondered if he could sneak out of the tent
once his brother fell asleep. Instead, Sam was the one that fell asleep first.
…
Sam woke with a start, his body covered in sweat. He was so hot. He felt the
familiar ache and hunger deep inside and knew his heat was starting. He had to
get out of the tent. When he crawled out the door and stood up, he felt a gush
of fluid in his shorts. He hadn’t even been wearing a pad and he cursed at the
mess.
“Sammy?” Dean called sleepily.
“I’m fine, Dean. Go back to sleep.” Sam said stiffly. He was panicking
inwardly.
“Are you sure?” Dean asked, now crawling out of the tent as well. Sam heard
Dean sniffing. “What’s that smell?”
Sam’s breath caught. He knew that Dean was smelling his slick dampened shorts
“It’s-it’s nothing, Dean.” Sam said.
Dean stepped closer to Sam. “It’s coming from you..” Dean said.
“I-“ Sam started to speak but then stopped. He didn’t know what to say. Dean
stepped closer and Sam was trembling. Dean’s smell filled his nostrils.
“You’re having a heat, aren’t you.” Dean said, his voice low. It wasn’t a
question.
Sam nodded. Dean knew that Sam had heats, and that they were uncomfortable for
him. But that was before he manifested as alpha. Now, Sam being in heat meant
something completely different to Dean. Something that would be difficult for
his alpha nature to resist. Sam knew he should move away, go back to the cabin,
or even go sleep in the car. But he was stuck in place as Dean closed the
remaining space between them. He sniffed at Sam.
“Oh God.” Dean breathed. “You smell so fucking good.”
“Dean.” Sam whimpered. His knees buckled and Dean caught him.
“I got you, Sammy.” Dean said soothingly, his hands gripping Sam’s arms. Sam
struggled to pull out of Dean’s grasp but Dean held him fast.
“Dean.” Sam protested weakly. “Let me go.”
“I can help you, Sammy.” Dean said boldly. “I hated hearing you suffer through
all those heats.” Sam looked at Dean sharply. Dean nodded and continued. “You
tried to hide it from me, but I heard you at night, whimpering and sobbing and
writhing on your bed in the room across the hall. When I was younger I didn’t
understand why you had to sleep across the hall once a month. When I got older,
I snuck up to the door and listened.”
“Oh my God.” Sam said, feeling mortified and ashamed. He was grateful that Dean
couldn’t see him blushing furiously in the dark. “I can’t believe you spied on
me.”
Dean nodded again. “And then last year, I snuck into the closet in that room.
And I watched you.”
“Dean!” Sam gasped, now feeling completely humiliated. “You didn’t!”
“I saw you take out that huge dildo and sink yourself down on it. I saw you
rock back and forth on it, fucking yourself with it until you finally came all
over yourself.” Dean’s voice was strained.
“Oh God.” Sam groaned. The thought of Dean watching him using that fake knot
was beyond arousing. He felt another gush of slick. Dean’s nostrils flared and
Sam knew that his brother had smelled it.
“And I thought that maybe after coming so hard you’d go to sleep, but instead
you started rocking yourself on it again, and you came again. And I could see
how wet the dildo was, how much of your slick covered the fake cock. I could
smell it. But it didn’t smell the way it does to me now.” Dean whispered.
“Watching from the closet, I tried to match you orgasm for orgasm, but I
couldn’t keep up. But I kept watching you, listening to you keen and moan with
that dildo buried deep inside you.”
“Fuck.” Sam sank down to the ground and Dean let him.  “You weren’t supposed to
see any of that.”
“I looked forward to your heats so fucking much after that.” Dean confessed.
“If I couldn’t watch you, I just listened to you through the door, and I could
picture you riding that dildo hard.”
“Jesus.” Sam gasped.
“Let me help you, Sam.” Dean said raggedly. “Oh please.”
“Dean.” Sam protested. “We can’t.”
“Dad doesn’t have to know.” Dean panted.
“Dean…no.” Sam said weakly.
Dean pulled Sam up to his feet and pushed him back into the tent. Sam didn’t
struggle; he was too far gone, his submissive omega nature taking over in the
presence of an alpha. Sam lay on his back. His shorts were completely soaked
now. Dean dragged the ruined shorts and briefs off of Sam’s legs and then
pushed his brother’s thighs apart.
“Ugh, I wish I could see.” Dean groaned. He pressed a finger against Sam’s hole
and it slipped in easily. “Fuck. So wet.”
“Dean…” Sam gasped.
Dean pulled his finger away and put it to his mouth, sucking Sam’s slick off of
it. “You taste even more amazing than you smell.” Dean growled.
Sam yelped in surprise when Dean pressed his lips against his weeping hole and
pushed his tongue inside. Dean kept his hands on Sam’s thighs, holding them up
and apart. Sam cried out as Dean licked him, thrusting his tongue inside and
slurping up his slick. Dean moaned against his ass as he continued to devour
Sam and Sam shuddered with pleasure.
“You’re gonna make me come, Dean!” Sam moaned.
“Mmmmmm.” Dean hummed against Sam’s opening. Sam was whimpering and sobbing as
Dean continued to taste him.
“Dean!” Sam moaned. “Fuck!” Sam ass bumped against Dean’s face as he came
jerkily, more slick flooding out his ass and drenching Dean’s nose, lips and
chin. His cock twitched and shot cum onto his stomach as he keened and
shuddered through the jolts of pleasure.
Dean raised his head once Sam had stilled, wiping his wet face with the back of
one hand. He plunged two fingers into Sam’s slick without warning and Sam cried
out and clenched around them.
“I’m gonna make you come all night long.” Dean rasped. “Fuck. You are so, so
wet.” Dean added another finger and thrust them in and out of Sam rapidly,
pressing in deep and hard.
“Dean!” Sam gasped. Dean had four fingers inside him now and continued to ram
them into Sam. Sam felt his second orgasm building. “Dean! Oh God! I’m coming!”
Sam sobbed as he pushed back onto Dean’s hand, his ass squeezing Dean’s fingers
hard as he spasmed around them.
“Now I’m gonna fuck you.” Dean said, not waiting for Sam to stop twitching. He
pulled his fingers out, making a show of sucking on them before pressing his
cock against Sam’s opening.
“Please, Dean…” Sam begged.
Dean slid inside easily, but his cock still stretched Sam wide, wider than that
ridiculous dildo ever had. Sam felt filled to the brim as Dean bottomed out and
pressed against him, making his knees touch his chest. Sam let his ankles rest
on Dean’s shoulders. Dean gazed into Sam’s eyes as he held himself deep inside.
“Sam!” Dean groaned as he pulled back slightly and then slammed back inside.
Sam moaned and writhed under his brother.
“Fuck me, Dean.” Sam urged. “Wreck me.” Dean started pumping in and out slowly.
“Faster!” Sam requested. Dean increased his pace. “Pound me into the ground!”
Sam growled.
“Fuck!” Dean gasped as he snapped his hips against Sam’s, burying himself to
the hilt. “You’re so fucking wet and tight.”
“Dean!” Sam groaned. Dean was hammering into him at a punishing pace, exactly
as he wanted.
They both moaned and gasped as their bodies moved together. And then they both
felt the beginnings of Dean’s knot. As Dean continued to thrust in and out of
Sam, his cock started catching on Sam’s rim.
“Oh my God, your knot...” Sam keened. It was the first real knot he had ever
had inside him. “You’re massive, Dean. Fuck.”
Dean grunted as it became harder and harder to move in and out of Sam, until
all Dean could do was grind against Sam. Sam’s muscles fluttered and clenched
around Dean’s knot.
“Dean!” Sam cried out when Dean reached down to stroke his brother. “I don’t
want to come without you..oh fuck!” Sam’s eyes rolled back and he bucked
against Dean.
“Sammy…” Dean said thickly. He felt a hot gush of slick around his cock as Sam
came with a howl. “Jesus fucking Christ.”
Dean came with an anguished moan, emptying himself deep inside as Sam’s hole
continued to spasm and milk his shaft. Sam was sobbing as Dean continued to
fill him with his cum. He felt so complete and full as Dean’s hips jerked
against him. When Dean let himself collapse on top of Sam, Sam wrapped his arms
around his brother and held him tight. He slid his legs off Dean’s shoulders
and let them fall open so Dean had more room to lie between them.
“Sammy…Sammy…” Dean groaned into Sam’s neck. Sam could feel Dean’s teeth. His
brother’s knot was fully swollen now and they would be locked together,
possibly for hours.
“Dean…” Sam murmured, stroking the back of Dean’s head.
“I want to bite you so badly.” Dean moaned, nipping lightly at Sam’s neck.
“Don’t…Please…” Sam gasped, but he couldn’t push Dean away if he wanted. His
brother’s knot held them fast.
“Sammy…Fuck…” Dean panted. “I’m stuck to you…”
“Yeah, that generally happens when an alpha fucks an omega.” Sam said
facetiously.
“Jesus how long is it gonna be like this…” Dean gasped.
“I dunno…hours?” Sam answered.
“Oh God we better separate before morning…if Dad finds us like this…” Dean
said, panic seeping into his voice, even as his cock twitched inside of Sam.
“I know.” Sam agreed. But he felt calm. He felt more at ease with himself than
he had been for years; ever since he had presented as an omega and his world
was turned upside down. But now it felt like his world was starting to right
itself a little. He felt Dean’s teeth on his neck again.
“How do you smell so fucking good to me?” Dean gasped. “You’ve never smelled
like this before. Like…cherry pie…and flowers…I don’t even know how to describe
it.”
Sam felt a surge of happiness in his chest; Dean found his scent so
irresistible, the same way Sam found his brother’s so tantalizing. It was a
sign that they were compatible. But they were brothers; it was taboo and their
father would disown them both. And he wouldn’t be able to go to Stanford. Not
as a mated omega, never mind one that was mated to his brother. He had been
planning to start his suppressants at the end of summer, but now he was feeling
reckless. Would Dean lose everything to be with him? His omega hormones were
clouding his judgement and Sam struggled to fight through the post-coital haze.
“You smell good to me too, Dean.” Sam sighed, as Dean nuzzled his neck and
inhaled deeply. Sam was determined to do the right thing. He would leave
tomorrow. Dean had a bright future ahead of him; alphas always did. Being with
Sam would ruin that for him.
Dean lay his head down on Sam’s chest and Sam stroked his brother’s sweaty hair
gently. A moment later he heard Dean snoring, and Sam smiled. He would stay
awake. He would make sure that he rolled away when Dean’s knot finally released
him, and make sure that Dean didn’t mark him with his teeth.
“I love you, Dean.” Sam whispered inside the dark tent.
Dean slept on.
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