Posted originally on the Archive_of_Our_Own at https://archiveofourown.org/
works/13148853.
  Rating:
      Explicit
  Archive Warning:
      Underage
  Category:
      F/M
  Fandom:
      Life_with_Derek
  Relationship:
      Casey_McDonald/Derek_Venturi, (past)_Casey_McDonald/Max_Miller
  Character:
      Casey_McDonald, Derek_Venturi, Marti_Venturi, Edwin_Venturi, Lizzie
      McDonald, Nora_McDonald, George_Venturi, Aunt_Madge_(Life_With_Derek),
      Sam_Richards_(Life_With_Derek)
  Additional Tags:
      Christmas, Christmas_Fluff, Christmas_Eve, Fluff_and_Smut, Porn_with
      Feelings, Warm_and_Fuzzy_Feelings, Family_Feels, Family_Dynamics, blended
      families_-_Freeform, Established_Relationship, Mutual_Pining, Friends
      With_Benefits, Post-Episode:_s03e16_A_Very_Derekus_Christmas, Missing
      Scene
  Stats:
      Published: 2017-12-25 Words: 2954
****** for yonder breaks a new and glorious morn ******
by blackorchids
Summary
     It's the season of giving, apparently, so Derek is maybe willing to
     have a talk about f-f-feelings. Only after Casey takes her top off,
     though.
Notes
     title from the song O, Holy Night, and I prefer the Mercy Me version,
     which you should all give a listen to, if you've never heard it!
     the underage warning is because they're both 16-17 in this, don't
     worry.
     this is shameless and indulgent and I hope you guys like it.
See the end of the work for more notes
Derek sort of feels bad about stomping up the stairs after completely blowing
off his dad, Nora, and Aunt Madge, but it’s completely overtaken by the fact
that he and Ralph hadn’t been able to even get out of Ontario before Ralphie
had been all but forced into a ditch, trying to avoid a collision with a
pinwheeling Sedan.
All of that flies out of his head when he slams his bedroom door shut and
slumps against it, groaning for a long, drawn-out moment before he’s
interrupted by someone’s prudeish cough for attention.
Lounging across his bed, which has since been made in the time between when
he’d left that morning and right that instant, is Casey, paused in flipping
through one of his car magazines, looking more than a little annoyed to see
him.
The fact that the entire view, bunny slippers and disdain and all, has popped
into his head during more than one of his solo Derek evenings does not keep him
from scoffing, full of that false bravado that gets her really irritated. “I’m
not in the mood, sweetcheeks,” he says, tilting his head to the side and
shooting over a simpering apologetic look that has her mouth—god, stop staring
at her mouth, Venturi—twisting up into a familiar sneer.
“Your aunt Madge has taken up residence in my room, and you’re supposed to be
out of the country by now and unable to get back through customs!” She hisses
bitchily, tossing aside his magazine like she wouldn’t have a fit if he treated
one of her books with so much carelessness. She pushes up onto her hands and
knees—good thing he’s an expert at not gawking—before rocking back on her
haunches, tossing her hair and crossing her arms under her chest.
She knows what she’s doing too, which makes it easier to kick her out. They
haven’t fooled around since before Max, but he’s definitely not going to be
anything even remotely on the same page as a rebound. He doesn’t have much, but
what dignity he does have he’s not willing to part with it so fast.
Derek shuts the door too quick, gets her on her ass and can hear her split his
name into two parts as she stomps across the landing to poor Lizzie’s room.
He texts Sam, complaining about how he and Ralph hadn’t made it past the border
because of the weather. Sam’s a filthy traitor, though, because he worries idly
that, if the weather was too bad to drive in, Casey and Lizzie’s flight might
not do so well.
[To: sammy boy | 18:29] idk ne thing abt tht
[To: sammy boy | 18:29] ull hafta ask her royal prissiness
[From: sammy boy | 18:30] so ur saying she’s got signal
[To: sammy boy | 18:30] im not saying ne thing
Downstairs he can hear too-loud Christmas music playing on their crappy old
boombox in the kitchen. Clearly Nora or his dad is trying to get the rest of
the Venturi-McDonald clan in the holiday spirit, but he can already imagine how
his dad’s presents after the holiday idea is going to go down with the kiddies,
and if Casey’s in such a bad mood, the rest of them will surely follow through,
whether they’re aware of it or not.
The music stops suddenly and Aunt Madge’s voice sounds sharper than he’s heard
her sound in years, so Derek lunges to the door, opening it as quietly as
possible so he can try and listen in. She’s berating them for being ungrateful
little brats, he bets.
“Uh,” Casey’s saying, sounding incredibly dubious. “Aunt Madge, I’m the last
person in the world who could convince Derek to do something he doesn’t want to
do.”
Derek doesn’t laugh, because it’s honestly not funny that she’s still so
completely clueless, but he does dive for his bed and get himself situated,
because Casey’s never met an adult she could say no to.
Sure enough, she comes barging into his room, sounding annoyed and impatient
already and the conversation hasn’t even started. Derek considers himself an
expert in agitating Casey, sure, but he can’t help but feel this intense
irritation is a little unfair.
“I can’t hear you,” he says serenely, not looking over at her. “I’m on the
beach.” If his mental beach has Casey in a stringy bikini and for-sure over
Max, no one has to know but him, and he’s ashamed enough for everyone.
She goes for the party-animal-Derek argument, but her voice is weak and
altogether unconvincing, because he bets she’s still not very much in the
holiday spirit either, even if she’s going to look down at him from her high
horse and pretend like she’s ready for blended-family festivities.
He’s just annoyed enough that he’s actually mean to her after she calls him
selfish, and she flinches back a little, looking away from him and frowning
contemplatively as she—god almighty—actually takes his words to heart.
Hearing her tell everyone goodnight is about when Derek decides he’s going to
save Christmas, even if he’s going to keep calling it Derekus out loud.
Fortunately, it’s not Casey coming to argue with him some more, because if she
cries he’s in just the right sort of mood to apologize, and that’s not really
what they do.
His aunt Madge comes into his room, looking around curiously before laying on
the flattery really quite thick. He pretends he doesn’t have a double meaning
hidden in his words when he says it just might not be meant to be, and manages
to keep a straight face when she agrees without hesitation.
He tells her that her guilt trip isn’t working, but he’s always been a sucker
for the women in his family, so he asks for an out and she’s more than happy to
give it.
Casey and Lizzie are a pair of sad sacks of girl in Lizzie’s bedroom, and while
Lizzie is obviously disappointed she’s not seeing her father, Casey’s voice is
a little scratchy, like she’s been crying and trying not to let anyone see,
which is what she does when she’s actually upset instead of just being
dramatic. His stomach twists up unpleasantly, the sour taste of guilt lingering
at the back of his mouth, but he snaps briskly and tells her to get over
herself because that’s just how they are.
Surprise at his sudden reinterest in the holiday startles her out of her slump,
but the expression on her face after Derek tells her aunt Madge just asked for
help doesn’t help with the guilt factor. She really doesn’t know anything.
He pushes that aside though, and puts them all through their paces, assigning
roles in his no-nonsense director’s voice and pretending he doesn’t feel her
impressed gaze on the side of his face when he patiently but quickly coaches Ed
and Lizzie through the beginning of the show. It’s his turn to watch her when
she helps Marti dress up in some of her clothes, taking accessorizing as
seriously as Marti does, offering suggestions and listening intently to Marti’s
opinions.
“There are five kids now, and they actually get along pretty well,” he says,
finishing off the tiny show in his best announcer’s voice and Casey smoothly
rises up from her knees—mind out of the gutter, Venturi—to politely remind
everyone that no, Derek and Casey actually don’t get along, sorry.
“Except for Casey and Derek,” he agrees in a more normal voice, trying not to
look over at her and trying not to look like he’s thought entirely non-sisterly
thoughts about her. Luckily, the adults are clapping and cooing, commenting
over Edwin’s wig and Marti’s necklaces, and all he has to do is bow a few times
and ham it up.
His aunt Madge thanks him entirely too earnestly for his comfort zone, so he
pushes a hat on over her hair and invents a dance at the top of his head.
Casey’s right behind him, on the same wavelength like always, easily following
his dance routine.
After dinner and putting the little sibs to bed, she comes into his room, quiet
and shy and smaller than usual in her ridiculous holiday-themed pajama outfit,
her hair pulled back into a braid.
Derek can tell she’s got something to say, but he can’t guess at what it might
be and that makes him edgy, so when he gestures for her to sit down, he
obstinately doesn’t move away from the center of the bed, daring her with his
gaze to take the safety of the desk chair.
She sits on the corner of his bed, looks at the palms of her hands, heaves a
huge breath.
“I’m not really upset about Max,” she says, and her inflection is off, because
it sounds like she’s telling him he’s wrong, when he knows she cried over the
boyfriend comment earlier that evening.
“I’m used to it, by now,” he tells her, shrugging carelessly, making to go back
to his magazine. She slaps it down, palm on his chest, separated by forty pages
of glossy car photos and a single thin cotton baseball shirt.
“The boyfriend comment didn’t upset me about Max,” she says again, sounding
frustrated. “You—he—”
“I really would rather not talk some more about the fascinating saga that is
Casey McDonald and her fantastically disappointing boyfriends, if you don’t
mind,” Derek says. Part of him wants to call her sis, because that always gets
her to back off, and the other part of him is aware that it’s a few minutes
until Christmas and even at his worst he would rather try and avoid making
Casey cry on Christmas.
“You wouldn’t be just a rebound,” is what she settles on, nodding once like
she’s come to an agreement with herself. She looks a little defiant, like she’s
challenging him to deny her claim, but he’s too busy having a heart attack,
because she’s actually, verbally, alluding to the pair of them in more than a
step-sib context. She looks away again, returning her blue-eyed gaze back to
the palms of her hands. “You have never been just a rebound,” she says, quieter
even than her last statement, clearly having lost most of her bravery.
Except this is obviously the bravest thing she’s ever done, and he’s at once
proud of her and indignant with her, because now it’s on him. If he says the
wrong thing, they won’t have happened because of him, and if he manages to
fumble through saying the right thing, they’ll have to eventually come clean to
the family because of him.
Casey has handed him complete control over their bizarre situation, and he has
never wanted to be in charge less.
She looks so nervous though, bracing for a rejection and ready to escape his
bed and his room as soon as he tells her to leave, and he guesses that it would
put an indefinite moratorium on the pair of them ever being anything more than
housemates, because they’ll never be able to be siblings.
He’s taking too long, thinking too much—how ironic, honestly—because she starts
to get up, mumbling a half-hearted I just wanted you to know, but he manages to
get with the program enough to lean forward and wrap his fingers around her
wrist, tugging her towards him that she ends up in an ungainly heap atop him.
“This was completely accidental,” he blurts out before she gets too scandalized
and she snorts, shifting and adjusting with really too much rocking of her hips
against his own. She settles into a familiar spot atop him, one leg on either
side of his, sitting backwards on her haunches once more, watching him
curiously.
And suddenly, before he says anything and they get into an argument and roll
around on his bed somewhere between wrestling and grinding for too long a
while, he absolutely has to kiss her. It’s been months and months, and he knows
him wanting to follow Sally to the fucking British Columbia had hurt her way
more than her fooling around with Max had hurt him.
I’m sorry, he says to her mouth, quiet enough that he can claim denial if she’s
out of practice enough to mention it, but she knows better than that, by now,
and just leans forward, getting a hand in his hair and kissing him back,
forgiveness and hopefulness in every gentle swipe of her thumb against his
jawline.
He tilts her head to the side with a gentle-but-firm grip on her braid, kisses
down the slender column of her neck, the scent of her lotion settling around
him in a haze. He thinks about one day being able to bite into the smooth skin
of her collarbones, leave a bruise there for Emily to giggle over and people to
notice, wonders if that should technically be a part of his no-PDA rule and why
it’s not.
Casey lets him work the laughably large red buttons of her ridiculous pajama
top, smirks a little when he groans upon finding she’s wearing nothing
underneath. Her smirk falters when he gets a hand on one of her breasts,
thumbing over a nipple carefully at the same time as he scrapes his teeth down
the line from her ear to her shoulder.
She arches her back and presses down against his hard-on as bold and unafraid
as always, scraping her nails down one of his arms as she gasps and grinds
against him, driving him crazy. His head is full of her, his senses overtaken,
and she’s whispering his name like a prayer, splitting it apart much the same
way as she does when she’s yelling at him—ask him why he takes so much pleasure
in annoying the shit out of her.
Casey is at once vulnerable and bossy like this, knows what she wants and isn’t
too shy to ask for it but comprised of slim taut muscle and delicate feminine
curves and oddly small when she’s out of her bulky pajamas. Derek knows he’s
scrappy, but Casey likes to grip his shoulders, and he knows he’s slowly
getting more broad, and, more importantly, he knows what she likes, which is to
be on top until she’s relaxed and clingy with the first orgasm.
She clearly thinks he’s taking too long with her breasts, tries to guide his
hands further down her body, skating his palms over her curved side and her
toned belly and arching a brow when he doesn’t immediately sink his fingers
beneath the elastic waistband of her stupid, stupid pajamas.
Sue him, he wants to take his time, because Casey, half-undressed and skin
bereft of makeup and bunny slippers still on her feet because her toes are
always cold—well, he likes all of the Caseys, finds her keener abilities as
endearing as he finds them frustrating, cannot help the bitter pride when she’s
dating someone else and he looks them in the eye and doesn’t mention he’s seen
her naked, has a fondness for her skirts and any time she wears those skin-
tight dancing outfits, but Casey like this, relaxed and sleepy and completely
uncovered after sneaking into his bedroom?
He’d never admit it, but this might be his favorite Casey of them all.
After he finally gets a hand in her pants, it’s short work until she’s coming,
a blissed out expression on her face and his name falling from her mouth on one
long, drawn-out exhalation, and she lets him turn them over so she’s cradled
between his pillows, her hair escaping from her braid and fanning out around
her head.
Derek can’t stop kissing her, barely even cares that he’s still hard and that
she’s not going to let them have sex because the family is home, can’t stop
hearing her voice playing in his head, over and over you have never been just a
rebound, cycling around his brain like it’s on a banner, being tugged by a tiny
brain-plane.
Barely cares, because he’s still a teenage boy, and he still loses the grace of
the kiss when she gets a hand on him, expert level at getting him off because
she knows just as much about what he likes as he does about her, and she wraps
her legs around his waist even though it can’t be comfortable with her arm at
that angle, and she guides his face into the crook of her neck, fingers tugging
on the too-long hair at the nape of his neck.
Derek comes too quickly, and, whenever they’ve done this in the past, he’s
always been overtaken by a frantic urge to keep going, to get her off as many
times as she’d let him, so he’s sure she wouldn’t be able to just write him off
as some casual teenaged fumbling, but she keeps her hand in his hair and wipes
her other one off on his sheets—thanks, Case—and keeps herself wrapped up
around him like a particularly sticky octopus, like she’s comfortable with him
lying atop her and panting slightly into her neck.
After a few minutes where he lets his heart rate return to a more steady pace,
he pulls himself up just a little so he can kiss her some more, pressing quick
intimate kisses to her mouth, the pair of them trading back and forth, simply
revelling in sharing the stolen moment with one another.
“Merry Christmas, D,” she whispers when they break for air, and he presses his
lips against hers for a longer kiss, hand curling over her side possessively,
not that he’d ever admit it.
“Merry Christmas, Case.”
End Notes
     happy holidays loveys!! come leave the gift of a prompt on my
     tumblr!! *wink wink*
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