Posted originally on the Archive_of_Our_Own at https://archiveofourown.org/
works/3989557.
  Rating:
      Explicit
  Archive Warning:
      Rape/Non-Con, Underage
  Category:
      M/M
  Fandom:
      Free!
  Relationship:
      Matsuoka_Rin/Nanase_Haruka
  Character:
      Nanase_Haruka, Matsuoka_Rin
  Additional Tags:
      Underage_Sex, Dubious_Consent, Anal_Sex, Pediatrician_Haru, Daddy_Kink,
      Child_Rin, Anal_Fingering, Anal_Plug, Hand_Jobs, Size_Kink, Age
      Difference, Size_Difference, Creampie, Dirty_Talk, Semi-Public_Sex,
      OOCness, Spit_Play
  Series:
      Part 4 of Kink_Fanfictions
  Stats:
      Published: 2015-05-27 Words: 2637
****** Doctor Games (1) ******
by wsakuya
Summary
     "Have you already had erections, Rin?" Haru asks and tries not to
     groan as Rin quietly nods again.
Notes
     PLEASE READ BEFORE YOU CONTINUE:
     This is merely a kink of mine. I do not support this kind of behavior
     in real life.
     I willingly write this because I have enough brain cells to separate
     fantasy from reality.
     Just because I am writing about Underage Sex does not mean that I
     ever wish this actually happening to children.
     If you have enough brain cells to understand this as well, then keep
     reading.
     If this is not your cup of tea, don't even bother.
     Thank you, and have fun!
See the end of the work for more notes
The nurse comes inside with a clipboard in her hands.
"Your next patients will be the Matsuoka siblings, Dr. Nanase," she says and
smiles. "Who do you want to see first?" 
Haru turns around, the ghost of a smile on his face that makes the nurse blush.
"Send Rin in first," he says and watches the door fall closed.
He adores the Matsuokas, they're his favourite patients. They're sweet, nice,
and so obedient. They do whatever Haru tells them to, and today he uses that to
his advantage.
Rin is a sweet, twelve-years old boy about to get into puberty. Haru can
practically see how much the little boy loves him, always beams like the sun
itself whenever he walks into the office.
The door opens, and Haru turns around, plastering a small and kind smile on his
face as Rin walks inside and grins back.
"Hey, Haru!" the boy chimes and jumps onto the cot, his short legs dangling off
the edge.
The black-haired man frowns.
"Didn't I tell you to call me doctor?" he asks and puts on his stethoscope.
He gets only a toothy grin in return, and Rin immediately hits the next topic.
"My mom said I've grown!"
Haru nods, and then asks, "Do your bones hurt?"
Rin nods silently, and Haru orders him to take off his shirt to check on him.
The man feels his blood rush down to his crotch as he sees Rin shiny skin, his
cute little nipples only waiting for him to abuse them.
He swallows and then presses the head of his stethoscope to Rin's belly,
starting lower before making his way up to the boy's babytits.
Haru pretends to be listening to whatever he's hearing, fooling the boy easily.
It's really not that difficult either. He's just plastering a concentrated
expression on his face, and that does the trick.
As he finally brushes over the pink, little buds, Rin gasps, his body suddenly
going stiff.
Haru looks up and eyes him with a heated look.
"Did that feel good?" he asks curiously and watches Rin nod in embarrassment,
his body eventually relaxing again.
That gives him the courage to keep going, and he nudges Rin's nipples again,
rubbing and pressing against them until they're red and stiff and pointing at
him proudly.
The boy lets out tiny and surprised gasps, wondering why exactly this is
feeling so good. His tummy is turning hot just like when taking a bath, and he
feels his lower regions getting warm as well.
"Have you already had erections, Rin?" Haru asks and tries not to groan as Rin
quietly nods again.
"It's good that your nipples feel good too," he says and strokes Rin's little
tits even rougher until he can see a small tent in the boy's pants.
He looks down just in time for Rin to do the same, and the boy's cheeks redden
in embarrassment.
"Don't worry, Rin, that's a normal reaction," he says and steps back. "Can you
tell me how you do it yourself? So I can check if you're doing it right."
That it's, that his trick to get whatever he wants. He's a doctor, so saying
'to check if you're doing it right' is the safest thing he can say without
getting in trouble. And the boy literally trusts him blindly.
Rin hesitates for a second before nodding again, and he opens his pants to pull
out his little penis.
It's even smaller than Haru imagined, all shiny and red, the foreskin still
pulled over his head.
Rin starts to stroke himself, his cheeks turning an even deeper shade of red as
he keeps his eyes glued to his erection.
He's too shy to look up, and Haru is glad, or else the little boy would have
seen his perverted gaze, how his breath is coming out rougher as he watches Rin
rub himself.
His fingers just so clasps around his penis, and sometimes when he strokes too
hard and pulls the foreskin with him, he has to wince because it still hurts.
"Here," Haru says and pours lube he got from one of the drawers over Rin's
little cock.
The boy hisses over the coldness, but then starts to gasp again as it's now
much easier to move his hand up and down.
Haru can already feel himself getting hard and decides to go even further.
"Did you know that there's a little button inside you that can make you feel
even better, Rin?" he asks and watches Rin shake his head, cheeks still bright
red.
"We have to check that it's working properly. Is that alright?"
He already pours a big amount of lube onto his finger before Rin even gives him
the OK.
He's supposed to stay professional and use gloves, but he's already so far gone
and just wants to feel Rin that he does it without.
With the boy constantly stroking his little penis, Haru nudges Rin's tiny
asshole with his middle finger, and then pushes inside.
He's enveloped with a tightness he's never felt before, feels it twitch and
clench around him as he thrusts up to the knuckle.
Rin has stopped stroking himself and is instead whining now, little tears
running down his reddened cheeks.
"Don't worry, Rin," Haru says. "It's always supposed to hurt at first."
He reaches over and starts to jerk Rin's tiny penis, notices how he only needs
two fingers alone to reach around and pleasure him while his other hand is
still working inside the boy's asshole. 
He feels Rin's cock twitch and jerk in his hand as he drags his finger out of
his puckered hole and shoves it right back in like a clockwork, over and over
again.
Rin moans, the pain long forgotten as the only thing he's feeling right now is
pleasure.
"Haru--" he whimpers, his hips by now doing what they want as they move in sync
with the man's movements and give an especially rough jerk as Haru adds a
second finger.
"Call me Daddy, Rin," he breathes, his hand snapping back and forth as he fucks
his fingers in and out.
The taut walls around him pull him in, squeeze and almost crush him as they
desperately try to keep him inside, swallow him whole just like a mouth would
do.
"D-daddy?" the boy asks confused, his tiny fingers grabbing the fabric of the
cot under him, his thoughts already too drunk to sanely ask why his doctor
wants to be called Daddy so desperately. Instead he just listens, drool flowing
out of his mouth like a river as he mewls, "Daddy-- feels good-- my butt feels
good--" 
Haru's breath is raged as he hears the words spilling out of Rin's mouth like a
mantra, feels his little penis and asshole twitch and shake for him in the
pleasure he's giving each of them.
He's missing the boy's prostate on purpose while he fucks his fingers inside,
only so he can say this, "Your button doesn't seem to work, Rin."
He pulls out his fingers and lets go of Rin's cock, much to the boy's
displeasure.
"We have to reach it with something bigger and longer," Haru says and takes a
step back. "Is that alright?"
Rin wastes no time in nodding his head up and down, too far gone to think
rationally now. Even though he's usually such a smart boy, Haru thinks.
The man hides his intentions by smiling sweetly and then pulls down the zipper
of his pants.
"Is that okay with you?" he asks and pulls out his cock, so heavy and wet in
his hand as it twitches upon seeing Rin's tiny, little asshole, pre-cum already
smeared over the head and further.
This time, Rin actually hesitates and bites on his lip, clearly interested in
Haru's sex, yet somehow scared. Luckily, he immediately voices his thoughts.
"Will it hurt?" he asks carefully, his eyes swiftly rushing up to meet Haru's
gaze before settling back on the big cock in front of him, watching how the man
leisurely strokes himself, and Rin unconsciously licks his lips as it twitches
under his stare, as if calling for him. 
Haru nods, but then realises that the boy can't even see it.
"At first, yes," he says, better not lying before Rin refuses to play along
after all. "But then you will feel really good. And we can check if your body
is alright as well."
He already knows he has won, but loves it anyways as Rin looks up to him, his
pupils wide and blown, eyelids barely open, and nods.
"Make me feel good again, please," he mewls, and then upon remembering adds,
"Daddy."
He hooks his arms around his knees and presses his legs up to his plumply
chest, all on his own, and proudly presents Haru his tiny, twitchy hole as
invitation.
It's breathing, almost as if it was whispering to him, telling him, 'take me,
fuck me, abuse me' in a sweet voice.
Haru wastes no time in pushing his pants down and entirely freeing his cock,
his hairy balls jiggling with the action.
He uses no condom, wants to feel Rin around him, feel those deliciously tight
walls milking his cock until every last drop has been squeezed out of him.
The lube that has run down the crack of Rin's ass is now coated around Haru's
thick cock, and he counts up quietly to three before pushing into Rin, forcing
his head past the tight rim which feels just like a kiss before he grinds along
the juicy flesh and finally settles inside.
His balls are pressed against Rin's little ass, and Haru watches breathlessly
the clearly visible bulge his cock is forming inside Rin's tummy.
The boy is whimpering again, tears running down his chubby cheeks as he's
hugging himself in a poor attempt to make the pain disappear.
Haru hates seeing Rin cry, and even more hates being the one making him. So he
leans down, nearly breaking the boy in two and kisses him on the lips; one hand
reaching up to jerk off his little penis while the other begins to play with
his babytits.
"It's okay, Rin, Daddy's here," Haru whispers against the boy's lips before
fucking his tongue without another warning into his mouth, his hips pulling
back before snapping forward again, lets himself get squeezed by Rin's tight
asshole.
He loves the welcoming gesture every time he does so, loves how the boy is
pulling him in instead of out, loves watching the huge bump disappear before
appearing again.
Rin has trouble breathing while Haru is abusing his mouth with his tongue, yet
mewls and shakes whenever the man dives back in, his cock never pausing in
fucking into his asshole.
"Daddy-- tummy feels weird--" Rin whines once as soon as Haru pulls his mouth
away and instead starts licking at his throat like a dog, drags his tongue over
the boy's non-existent Adam's Apple and then opens up Rin's mouth with a thumb,
spitting inside without another warning.
But Rin doesn't mind at all. Instead he swallows his Daddy's spit, opens up his
mouth on his own accord again and sticks out his tongue, waiting eagerly for
his reward.
He's already so far gone, his mind drunken with pleasure, with feelings he's
never felt before as Haru fucks into him like a lifeless doll.
His body is bent in half, pressed down almost painfully on the cot, and even if
he wanted to run away, he couldn't.
Haru is caging him like a lion his catch, slowly eating him up without another
care, and Rin just takes it, doesn't resist or protest; simply because he loves
feeling Haru fuck into his tiny hole and tear him open again and again.
He loves being used like a fuck hole. He just wants more. "Daddy, more-- push
your weenie deeper into me--"
Haru laughs breathlessly and reaches up to caress Rin's drool-covered cheek.
"You like that, don't you, baby?" he asks and opens up the boy's mouth again.
"When Daddy fucks you like this?"
He spits inside again, watches his babyboy swallow it right away and open his
mouth again, hoping and waiting for more.
His cock is still pounding into that tight, little hole, swallowing and
massaging him like a pro.
The walls are getting juicer with each thrust, and Haru's sure it's not only
his pre-cum coating them, painting them in his milk. It's Rin as well, making
himself wet for his Daddy.
"Your button works fine, doesn't it, baby?" he asks, hitting Rin's prostate
over and over again. It's too easy since the boy is so small compared to his
fat cock, looks so delicate and vulnerable, and Haru loves it; how helpless Rin
is feeling under him, that he has no choice but cling to Haru in desperation.
Rin just nods silently, apart from the moans of course, and swallows more of
the man's spit.
"Do you want my milk, baby? Daddy's milk inside you?" Haru asks and speeds up
as much as he can, his hips mindlessly jerking and shaking with each thrust
like a rattling machine. "It's Daddy's medicine for you. Gonna feel so good,
baby--"
Rin nods again, sobbing with each thrust and having no other choice as to cling
hysterically to the man above him and his labor coat.
"Daddy-- milk-- give me milk--" And then Rin screams as his first, actual
orgasm hits him, little strings of babycum shooting onto his chest and mingling
with his sweat, and Haru has never been happier that the walls are sound-proof.
As he feels his baby squeeze around him like mad, he gives his last thrust,
pushing in as deep as possible into Rin, loaded balls slapping against the
small ass as he watches the bulge that is Rin's belly grow in size and his cum
shoots out, milking the boy thoroughly - so much that it actually is too much
and half of it squirts out of Rin's asshole past Haru's cock onto the floor.
Rin lets out another scream as his tummy keeps growing, and he calls out
"Daddy's milk! Daddy's milk!" over and over again before Haru pulls out.
Another load of his cum splashes onto the floor before Haru pushes everything
back with his finger.
"Squeeze, baby, keep my milk inside," he says and Rin does as he says, can feel
Rin do it around his finger, and he can't help but keep fucking it in and out,
taking in another one and watch Rin's belly grow with every push.
Then him hits an idea.
"Baby, keep your hole wit your hands closed so nothing spills out," Haru says.
"Give me a second."
As he pulls out, Rin immediately closes his tiny hands around his hole, trying
to not let anything out while he's waiting eagerly for his Daddy, even though
his body is still weak and shaking.
Haru rummages through his desk before eventually finding what he was looking
for.
A little, red plug perfect for Rin's little, red hole.
With eager expression and cock still hanging out of his pants, Haru steps back
in front of Rin and pushes his hands away, immediately thrusting the little
accessories into the boy's quivering asshole, watching it clench around it as
soon as it's perfectly settled, and Haru sighs.
"That way you can keep Daddy's medicine inside you," the man says and helps Rin
put his clothes back on.
"Thank you, Daddy," Rin says and kisses Haru shyly on the lips before jumping
off the cot.
He shakes his hips a few times, trying to get used to the foreign feeling of
the plug inside him, and then opens the door. "Bye, Haru!"
The doctor smiles. "Now get your sister inside."
End Notes
     Sequel: Doctor_Games_(2)
     (I'm not forcing you to comment on this work since I know that many
     people feel uncomfortable with commenting on sexual-themed
     fanfictions, so I would be happy if you left a kudo. Thank you!)
     PS: Send me a prompt, http://wskprompts.tumblr.com/ask
     If the ask box should be closed, then it's because I'm taking no
     prompts at the moment. Please be patient and wait for my next post,
     and then check my ask box again.
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