Posted originally on the Archive_of_Our_Own at https://archiveofourown.org/
works/11857872.
  Rating:
      Explicit
  Archive Warning:
      Underage
  Category:
      F/M
  Fandom:
      Supernatural
  Relationship:
      Dean_Winchester/Sam_Winchester
  Additional Tags:
      female_alpha/omega_male, Female_Alpha, Alpha/Beta/Omega_Dynamics,
      Cisswap, Female_Dean_Winchester, Dom/sub_Undertones, Plot_What_Plot/Porn
      Without_Plot, Angst, Switching, the_slightest_of_dub-con, Double
      Penetration, Size_Difference
  Series:
      Part 2 of Harder_Better_Faster_Stronger
  Collections:
      SPN_ABO_Bingo
  Stats:
      Published: 2017-08-20 Words: 1992
****** Harder ******
by IndridGrey
Summary
     Sam wakes Dee up for sex. It ends up being a bit less vanilla than
     either of them were anticipating.
     (can stand on own, do not need to have read prequel)
Notes
     One of these days I'll make a post explaining how I imagine ABO
     anatomy works. In the meantime, just go with it :)
     This is set 2-3 months after Better
See the end of the work for more notes
Dee had been bone tired earlier—had almost passed out in the shower while
scrubbing off grave dirt—so didn’t wake all the way up until Sam made a
frustrated noise and jerked his hips hard against her.  The last of the
pleasant half-asleep haze that she’d been in since Sam had rolled her onto her
back faded away and she opened her eyes to the dark room.  Another impatient
noise and teeth on her nipple had Dee burying a hand into Sam’s bedhead and
pushing her thigh back against his erection.  She sighed his name and took
stock.
He was naked against her, which wasn’t surprising since he slept that way.  It
was a little surprising that her sleeping shirt was pushed up to her neck and
he was rutting against her and sucking her tits.  He was usually good at
waiting for permission before trying anything past kissing.  She breathed in
deep and, while he was seeping pheromones, nothing smelled like a heat.  Which
meant it was just her baby brother desperate to fuck her, not his designation. 
A dirty thrill zipped through her and she rocked up into him.
She grabbed his ass to keep his twitching hips close and whispered, “You wanna
fuck me, Sammy?”
Sam groaned deep in his throat and wiggled further up.  “God, yes, please.”
He muffled her answering groan with a series of close-mouthed kisses, ever
considerate of how gross she found morning-breath kissing.  She tightened her
grip on his hair to pull him away and reached out to turn on the bedside lamp. 
He whined at the movement and with the lamp on she could see the puppy eyes.
“Poor baby, all those teenage hormones.  Get me wet first,”—she nipped his
bottom lip—“then you can do whatever you want.”  She grinned when pre-come
smeared across her thigh with his next thrust.  He got a hand on her erection
through her panties and gave a few hard rubs that had her gasping.  Then he was
up on his knees, yanking her underwear down and off, and she had her shirt off
onto the floor before he pressed her back into the mattress.
He settled low on her again, slotted between her legs where his dick was
against her thigh, her dick was against his stomach, and his mouth was in the
perfect position to lavish her chest with relentless attention.  She didn’t
think there’d been a single day without at least one hickey somewhere on her
torso since they’d started this.  Her nipples were well on their way to being
sore by the time his hips stuttered and he reached down past her dick to find
her drenched.
Dee felt a flicker of confusion when he nudged her onto her stomach and then
onto her knees before tucking in close.  He was still waiting for a growth
spurt and they could never get the angle right in this position for him to stop
slipping out, so what was he doing?
Two fingers breached her roughly and she moaned and clawed the pillow.  Sam
pumped and spread them and Dee could feel her vagina unfolding for him and fuck
if that wasn’t hot.  God, she couldn’t wait until he was grown—his dick may
always be on the small side since he was an omega, but she really hoped he got
big enough to stuff her full.  Even with a small cock, though, they could make
this position work once he got taller.
Now, though, she was getting a little impatient.  They’d definitely established
that he wanted to fuck her, and she was more than wet enough, so why was he
stalling?
She was about to voice this, but then the fingers pushed hard towards her naval
and something else pushed at her entrance and holy—
“Fuuuuuuuuuck ungh,” she groaned into the pillow, probably drooling a little. 
Sammy, the genius, was two steps ahead of her on the whole ‘stuff Dee full’
front and her vagina was shuddering around two fingers and his cock.  He made a
guttural noise but didn’t move and Dee flailed a hand behind her to grab a
thigh or buttock.  “S-Sam, fuck me already!”
Apparently, that was all the permission he needed and he went from 0 to 60 in
about ten seconds with short vicious shoves into her and she couldn’t catch her
breath.  She rose slightly onto her elbows to keep from suffocating in a
pillow, but then her hypersensitive nipples were brushing against the bed with
every rough thrust and little noises started punctuating her gasps.  Her
insides were winding up faster than they had since her first handful of sexual
encounters and then Sam moved his fingers.  He crooked and dragged hard against
the spot linked to the bottom of her knot and oh fuck that was—
“I’m gonna—no, don’t—Sam!”
Next thing she knew she was jarringly empty and being pushed onto her back
again.  She had barely sucked in a full breath when Sam sank onto her dick in
reverse cowgirl and stuffed three fingers into her, crowding the air back out
of her lungs.  She watched his taut, wet hole as he rode her and wished she
could see his pretty pink cock, too.  His fingers twisted up against that spot
in her again and she swore as her knot swelled.  Oh no.
She wrapped her fingers just above her knot, barely winced when his fingers
popped out of her when she yanked him back, and rolled them on their sides.  He
tried to arch back onto her knot and whimpered when he hit her hand instead. 
So he was going to be like that.
She growled, pulled out, sat up, pushed him onto his back, hooked his feet over
her shoulders so his ass rose off the bed, and crawled up until they were in
flipped roles of the position he usually fucked her in.  She reentered him
slowly and he whined and tried yet again to arch onto her when she was only
halfway in.  Sam stilled with a wide-eyed look when she wrapped a firm hand
around his throat, where in less than a year she’d get to put a collar or bite
or both.  She growled again, adding an alpha pitch, and he relaxed into her
pin.  She got a hand on his dick, still wet from her, and jerked it teasingly
gentle as she pushed down into him.
They used this position to accommodate his short legs and cock, neither of
which were problems for Dee, and she enjoyed watching his face as he felt her
deeper than ever before.  She still had an inch until her knot when she hit his
cervix and he spasmed with a shout.  Too sensitive outside of heat, probably,
so she backed off a few inches.
Sam settled back down and tentatively raised a hand to cup one of her tits. 
She rocked into him gently and tightened her fingers around his glans.  His
groan vibrated against her hand on his throat and he brought his free hand up
to her other tit.  She got a few soft thrusts in before he pinched her nipples,
reawakening the soreness.  He kept the tight grip and twisted slightly and she
barely kept from slamming into him or choking him out.  Her grip on his
cockhead turned harsh and she fucked into him hard, dislodging a startled moan
under her hand.  He only lasted two more thrusts before his voice cracked on
his scream as he came into her hand.  She kept fucking him through his orgasm,
not even letting up when the contractions around her dick slowed and he started
making small, uncomfortable noises.  There were tears in his eyes when they
focused back on her and he squeezed her tits tight, trapping her nipples
mercilessly between the hard joints of his fingers, and she yelped as she
climaxed and the first of her ejaculate spilled into him.
When the waves of her orgasm softened, she removed the hand curled around his
neck and grabbed a pillow to support his hips before she eased his legs back
onto the bed.  She awkwardly settled against him, bearing her weight on one
elbow.  She eyed the pack of baby wipes on the nightstand as she brought up the
hand covered in spunk and was startled when Sam opened his mouth wide with an
expectant look.  He wasn’t feeling any of the hesitance she was, and as soon as
her hand got close enough, he started licking it clean.  She held her breath,
waiting for him to bite her or something, but he just look blissed out.  Even
after her hand was clean, he held two of her fingers heavy on his tongue, his
eyes half-mast and unfocused.  It suddenly occurred to her that he’d probably
be into warming her cock.  That—that thought was just going to have to wait for
another night.
He gave a quiet whine when she pulled her hand back to get to the baby wipes,
and squirmed a little at the cold touch when she cleaned off his soft cock. 
She swiped over her hand, too, but didn’t pull out yet to wipe all of that
down.  They had a deal.  But apparently Sam needed to be reminded.
Even as dazed as he seemed, he still picked up on the shift in her body
language.  He watched her toss the baby wipe onto the nightstand and sounded
every bit like a petulant teenager when he defended, “You said I could do
whatever I wanted.”
“I didn’t think I needed to state the obvious when we’ve been over this more
than once, Sam.”
“Hmph.”
She sighed and nuzzled his sweat-damp temple.  “Unbonded knotting can lead to
things we need to plan for first, baby boy.  I have work, you have school.  We
can’t just skip four days without warning if you go into heat.  And we can’t
risk CPS getting involved if I bite you before your birthday.”
“I know, I know.”
They simmered in melancholy for a few beats before Dee’s next ejaculation made
them both gasp and twitch with sensation.  That reminded her—
“How do you know how to make my knot pop like that? Have you been watching porn
without me?  Is it that blond kid?  Something you need to tell me?”
He scoffed, not missing a beat.  “I found some books in the library.”
“You read porno in the library?”  She injected her tone with all the fake
scandal she could manage and it paid off when he clapped a hand over his eyes.
“They were anatomy books, Dee!”  He squeaked.
“Is that what they’re calling them these days?  Doesn’t sound very sexy.”
“Shut up!”
She touched her nose to his and could practically feel how gooey her expression
was.  “Make me.”
He peeked through his fingers then relocated them to her jaw to tilt her head. 
His kisses were a little harder than usual, frustration still just below the
surface, but Dee gave back just as hard.  If it weren’t a couple hours from
dawn after a hunt, and if their breath was less disgusting and therefore their
kisses deeper, they might have wound up making out and fucking the frustration
away.
As it was, Sam was half-asleep when the last dregs of Dee’s orgasm pulsed into
him, and Dee was barely coordinated enough to dig the plug out of the drawer,
wrestle with the drawstring of its pouch, and slip it in without rousing him. 
She got it in quick enough that he didn’t need wiping down, and she hissed as
she baby-wiped herself.
She turned off the lamp, settled on her back, and pulled the covers back over
them both.  Sam turned onto his side just as she started drifting.  He wiggled
closer and one last shock of sensation from him laying his head on her sore
chest followed her into sleep.
End Notes
     This is for the double penetration square on my spn abo bingo card
     The next part of this series will be a little longer so may take a
     while to write, just a heads up
     Concrit is welcomed and kudos/comments make my day!
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