Posted originally on the Archive_of_Our_Own at https://archiveofourown.org/
works/1664507.
  Rating:
      Explicit
  Archive Warning:
      Underage
  Category:
      M/M
  Fandom:
      Ao_no_Exorcist_|_Blue_Exorcist
  Relationship:
      Okumura_Rin/Okumura_Yukio
  Character:
      Okumura_Rin, Okumura_Yukio
  Additional Tags:
      Twincest, Plot_What_Plot/Porn_Without_Plot, Tail_Sex
  Stats:
      Published: 2014-05-20 Words: 4685
****** Twincest ******
by Calimon1991
Summary
     Just porn, my first... yeah...
Rin panted harshly as he stumbled into the room that he and his brother shared.
He had no idea what the hell was going on; he was just so hot and felt so
strange.
A moan escaped his lips as he loosened the tie around his neck, managing to
make his way over to his bed as he did so, flopping onto it when he reached it.
“What the hell?”  He muttered.
Once he had the knot undone he threw his tie on the ground.
The strip of fabric was soon joined by his school jacket and when Rin found
that he was still way too hot his shirt followed.
“God.”  He whimpered as he wiggled out of his pants too; he just couldn’t stand
the feel of the fabric against his skin.
He had no idea what was going on, but his whole body seemed to be way over
sensitive.  Every brush of fabric against his skin had his body shivering.
Rin was left in just his boxers, but even that seemed to be too much clothing.
“Fu- ng.”  He moaned weakly as he fell onto his side on his bed, “What the
hell?”  He muttered again.
He curled up in a ball, trying to just stay perfectly still and see if this
wretched feeling would go away on its own, but before long he found his hand
wondering down his skin, almost as if by its own volition.
“Ngh.”  He moaned again as he pushed his hand into his boxers, wrapping his
hand around the hard flesh beyond.
He slowly started stroking himself, unable to stop; he was just so hard.
His panting grew faster and louder as he sped up his movement; he really just
wanted to get it over with, hopefully then he would feel better.
Rin shoved his boxers down his legs before flinging himself onto his back and
stroking himself faster; it just wasn’t enough though; he couldn’t get off.
A whine escaped his lips as he grew more and more frustrated.
He was sprawled over the covers on his bed, his legs spread wide as he
masturbated, but he didn’t seem to care; the fact that his brother could come
into the room at any moment seemed to have completely blown the horny teenagers
mind.
Rin rolled over on to his stomach; it wasn’t nearly as comfortable as his
previous position, but he found that laying on his tail was unbearable; the
sensitive appendage was being even more sensitive in that moment.
The demon groaned as he stilled his hand for a moment, removing it from the
aching organ it had been wrapped around to bring it around to his tail.
He gasped as he brushed the lightly furred skin.
Yep, definitely sensitive.
He rubbed at the skin where his tail and back side met before his fingers
trailed down a little lower.
He gasped again when his fingers brushed softly against the puckered hole below
his tail.
He had no idea what he was doing, but all his hazed mind could think about was
how good that had felt.
Rin pressed his finger against the hole.
“Ha…”
The digit slowly slid passed the tight ring of muscles, but it didn’t get very
far before Rin grew uncomfortable with the sting that came from the dry
penetration.
He removed the finger before bringing it to his mouth, lathering it, and a few
of its brothers, with saliva, and returning it to the sensitive area.
Once again he tried pressing the figure passed the ring of muscles and this
time he managed to get it all the way to the third knuckle.
He gasped sharply.
It still hurt a little, but fortunately for the boy the pleasure outweighed the
pain.
After allowing his body to get used to the small intrusion he slowly began to
pump the finger in and out of the now willing hole.
“Ngh!”
He moaned loudly as his finger rubbed against his inner walls.
Soon he felt a little bolder; he slowly pressed another one of the still slick-
with-saliva digits into his hole, stretching the muscles as if preparing
himself for something larger.
When his body had grown accustomed to the sliding feel of the two fingers
pumping in and out he slowly started scissoring them, moving them around to try
and loosen himself up as much as possible.
When he felt he was ready he slipped one more finger in.
“Ah!”
It was so good.
It hurt a little, but the pleasure was so worth it.
He slammed the fingers in as far as he could and was rewarded with a shock of
pleasure shooting up his spine when he bumped against a very sensitive spot.
He rubbed at the spot, moaning and mewling as pleasure coursed through his
body.
But soon even that wasn’t enough for the poor boy.
Rin felt like crying, he was so hard, but he just couldn’t seem to get off.
He wanted to press his fingers harder against the sensitive skin that he had
found, but his fingers couldn’t reach any farther.
He needed something longer.
At that moment his tail, which had been thrashing around near the bottom of the
bed, slapped against his leg.
He paused as he removed his fingers from himself.
He looked at his tail for a few long moments.
If he had been in his right mind he never would have allowed the thought to
cross his mind, but at that moment he couldn’t find it in himself to give a
damn.
He grabbed the squirming appendage, gasping sharply when he grabbed it a little
too harshly, before bringing the tip to his mouth.
He licked the slightly tufted tip and moaned at the feel; this encouraged him
to mouth the tip, sucking on it and wetting as much of it as he could.
As he continued to suck on his tail he trailed his free hand back down his body
to wrap it, once again, around his aching arousal.
After a few moments Rin released his tail and stilled, panting harshly for a
few moments as if to get himself to calm down, even if just a little bit.
This reprieve only lasted for a short time; though, as he gingerly grabbed his
tail once again.
He slowly moved the tip to his sphincter, brushing the furred tip against the
sensitive hole.
He gasped at the feeling that he received, not only from the tender opening,
but also from the sensitive tail tip.
He moaned as he pressed the tip harder against the opening, slowly pressing it
passed the tight ring of muscles until he had to pause and allow his body to
adjust to the larger intrusion.
He gasped for breath as he allowed his body to grow accustomed to the feeling
of being stretched.
When he felt that he could go on he slowly pressed his tail farther into his
body, by this time he no longer needed his hand to help guide his tail into his
body and instead was able to press his tail in on its own.
A sharp intake of breath and he was arching off of the bed as his tail firmly
prodded against the sensitive mound of nerves that he had discovered earlier.
“Ah!”
He wasn’t even bothering to keep his voice down; it was a good thing that he
and Yukio had the whole dorm to themselves.
Rin stayed like that for a few moments, allowing himself to calm down a little,
but once he was more relaxed he slowly pulled his tail from himself before
pressing it back in.
Another loud moan.
He picked up his pace; pulling his tail out and shoving it back in.
His breathing became labored as he sped up his movements.
As his tail worked he once again brought the fingers of one hand to wrap around
his member, stroking himself in time with the thrusts of his tail.
He was definitely getting close now.
The pleasure coursing through his body was almost too much.
“Ngh…  S- So good.”  He muttered against his pillow, shoving his face into the
fabric as if trying to hide from all of the stimulation.
The poor boy’s body was drenched with sweat and it was obvious that he wasn’t
going to last much longer.
“A- Ah!”
He almost screamed as he gave his cock a few last tugs before he came.
His body shuddered and jerked as his orgasm was ripped from him; his tail still
managing to pump wildly in and out of his hole.
“Hah.”
He collapsed onto the bed, allowing his hand to drop from his spent arousal and
his tail to slip from his body.
Rin lay in his bed, motionless except for his heavy breathing.
Little did he know wide eyes were staring at him.
 
Yukio stared at his brother, still trying to come to grips with what he had
just seen.
He had stayed behind in his classroom, grading papers so that he could get them
out of the way.
He definitely hadn’t expected to walk in on this.
Yukio had walked in on his older twin brother just as he started shuddering on
his bed.
He would have ducked back out of the room, but he had been so surprised to see
his brother in such a state that he couldn’t do anything, but stare helplessly
at the other boy as he climaxed.
Yukio let out a breath, making sure to stay as quiet as possible for the
moment; it seemed that his brother had yet to notice him and he wanted to keep
it that way for the time being.
What Yukio also hadn’t expected was the way his body had reacted to seeing Rin
that way.
The boy had been fucking himself with his own tail and Yukio was terrified to
admit to himself that that had turned him on beyond all reason.
“Nii-san.”  Yukio whispered softly, figuring that he should warn the other that
he was there sooner or later.
The other boy jolted up, staring at Yukio with wide eyes.
“Y- Yukio!”
He quickly scrambled to pull the covers of his bed over himself.
Yukio nodded as he looked away from the other, adjusting his glasses as he
moved further into the room, placing his stuff down next to his desk.
Rin stammered incoherently as he watched the younger boy, not being able to
think of what to say.
How long had his twin been there?  What all had he seen?
Yukio stood in front of his desk, trying to calm himself; he couldn’t bring
himself to look at his brother at the moment; he was afraid that if he did he
would do something that he would regret.
“Nii-san, I think it would be best that if you were going to do that again, you
lock the door or else give me some kind of warning.”
Rin bit his lip, “God, I- I’m sorry Yukio…  I… I don’t know what happened.”
“There is no need for you to apologize, just please make sure that it doesn’t
happen again.”
Rin nodded despite the fact that his brother couldn’t see him.
He buried his face in the covers for a few moments; he wanted nothing more than
to hide under them and disappear, but he knew that that wouldn’t solve
anything.
“I- I’m gonna go t- take a shower.”  Rin muttered, “So, uh, can you not look
for a second.”
Yukio simply nodded.
Rin stared at the back of his younger brother’s head for a moment before
mentally shaking himself.
He slowly pushed the covers off of himself and turned to gather up some clothes
to change into when he was done.
It was at this moment that Yukio couldn’t stop himself from taking a peek at
the shorter male; he was greeted to his brother’s ass basically sticking up in
the air as he bent over to pick up his clothes.
Yukio gasped; his cock twitched in his pants.
There was no way he could let the other leave now.
Rin made to get up and leave the room, but Yukio stopped him.
“Nii-san.”  He whispered.
Rin spun around to face the other, a deep blush staining his cheeks as he used
his clothes to cover himself.
“Yukio!  I told you not to look.”
“Gomen, nii-san.”  Yukio said softly as he slowly walked over to his brother;
he didn’t really sound sorry.
Rin watched his brother with wide eyes as he slowly backed away from his
approaching sibling.
“Wh- What are you doing Yukio?”
Yukio stopped in front of Rin when he realized that he had the other boy
cornered.
“Put your clothes down Rin.”
The demon gasped at the tone in his brother’s voice; for some reason he found
himself wanting to obey the other boy, and so, despite his better judgment, he
found himself dropping the mentioned items.
Yukio slowly trailed his eyes over all of the pale skin that had been revealed,
zoning in on the slightly aroused fleshed between his older brother’s legs.
Rin may have just cum, but with the way his brother was looking at him it
seemed to be exciting him for some reason he couldn’t even begin to explain.
Yukio looked back up at Rin’s face.
Rin looked back at him.
The two stared at each other for a few short moments before Yukio leaned
forward and pressed his lips to the slightly moist ones of his older brother.
Rin gasped against Yukio’s lips, but he didn’t pull back, instead he moaned and
wrapped his arms around the slightly taller boy’s neck, opening his mouth
slightly and encouraging Yukio to explore the orifice with his tongue.
Yukio groaned as he pulled his older brother closer to his body, shoving his
tongue into the other boy’s mouth as he had offered.
The kiss lasted for several long moments until they were forced to pull apart
for breath.
Yukio rested his forehead against Rin’s as he stared into the other boy’s eyes,
“Nii-san.”  He muttered softly, his breath brushing across the other boy’s
skin, “We shouldn’t be doing this.”
Rin panted lightly and nodded; he knew that what Yukio was saying was correct,
but he didn’t want to stop.
Fortunately for the smaller male, Yukio didn’t seem to want to stop either.
Yukio let out another groan before leaning forward again and taking his
brother’s lips in another demanding kiss.
“God nii-san.”  He gasped out between kisses, “We really-“  Another kiss,
“Shouldn’t.”
“Yukio.”  Rin whimpered against his brother’s lips, “Please, I want…”
Yukio gasped before pulling away from his brother.  He stared at the smaller
teen for a few moments before finally grabbing him and basically shoving him
back onto his bed.
He wanted nothing more than to smother the other with more kisses, but first he
had to get rid of these god-forsaken clothes.
“Yukio…”  Rin whimpered again, taking the rough treatment that Yukio was giving
him as a sign that the other boy wasn’t going to continue.
“Calm down, nii-san.”  Yukio soothed as he unbuttoned his long trench coat.
Usually he was able to deal with the buttons very quickly, but with how much he
was trying to rush it, he kept fumbling with them.
“Just a moment nii-san.”  He muttered when he finally managed to get the last
button undone before discarding the jacket.
Rin leaned up onto his elbows and watched his younger brother undress.
After a few moments of watching the taller boy fumble with the buttons of his
shirt as well, Rin decided that it was time to take things into his own hands.
Rin pushed himself back off of the bed and kneeled down in front of the
frustrated boy.
Yukio paused in de-vesting himself as he watched the tailed boy, “Nii-san, what
are you doing?”
The demon raised his hands to his brother’s hips, “Helping.”  He whispered
before bringing a hand to unbutton and unzip the front of the boy’s pants.
Yukio’s hands were frozen as he found himself transfixed on his brother.
Rin whimpered again, “Hurry up Yukio.”  He begged as he gave the other a
pleading look.
Yukio nodded numbly before going back to the unhelpful buttons; he was unable
to take his eyes from his brother’s face though.
After seeing that Yukio had returned to getting his clothes off once again, Rin
returned to the task that he had set himself.
He pulled down his brother’s pants and was greeted to the very large tent in
his brother’s boxers; the front had already started to dampen with how excited
the other boy was.
Rin pressed his face too his brother’s crouch and nuzzled, breathing in the
musky scent of the other boy.
Yukio’s fingers fumbled with the button he was on again at the sudden pressure
against the sensitive place; he quickly tried to speed up what he was doing
though, wanting to touch his brother some more.
When Rin was done nuzzling the other he slowly pulled away to pull down the
other boy’s boxers, causing the aroused organ to spring forward.
Yukio gasped at the sudden cool air against his sensitive skin.
“Nii-san.”
“Please Yukio.”  Rin whimpered as he looked back up at the other.
Yukio nodded numbly, returning to the stubborn buttons.
Happy with that Rin turned his attention back to the younger boy’s cock.
He slowly moved forward and licked the liquid that was leaking out of the slit.
Yukio gasped, his knees almost turning to jelly, but he forced himself to be
strong.
Rin gave his brother a quick glance to make sure that he kept up with those
damned buttons before giving the penis in front of him another quick lick.
He seemed to be pleased with the taste and became a little more bold; leaning
in a little closer so that he could mouth the tip.
Yukio groaned; did his brother actually think that this was going to help him? 
All it was doing was getting him so much harder and making it basically
impossible to get these damned buttons undone.
He wasn’t going to complain though; the feel of his brother’s mouth on his cock
felt amazing.
Rin sucked softly at the tip, glancing up at his younger brother every time he
made a noise.  He was pleased that he was able to make the other make such
pleasured sounds.
Rin sucked harshly on the tip before raising his hand to grip the base of the
other boy’s cock, holding it still so that he could get more of it into his
mouth.
Finally Yukio managed to get the last button undone and when he had done so he
buried both hands in his older twin’s hair, trying to get some form of balance
so that he didn’t topple over thanks to his weakened knees.
Rin moaned softly around the warm flesh in his mouth at the other’s grip on his
hair; the vibrations made Yukio cry out in pleasure.
“Nii-san, God, that feels so good.”
“Ngh.”  Rin muttered against the other’s skin.
Yukio groaned.
Rin smiled around the thick flesh before closing his eyes and sucking hard.
“Fu-!”  Yukio gasped.
If Rin had been in his right mind he would have commented on the fact that the
other had almost let a curse word slip, but he was much too interested in the
aroused organ in his mouth.
He released the base of his brother’s cock and forced himself to surpass his
gag-reflex so that he could take the other boy to the base.
Yukio breathed harshly as he gripped his brother’s hair harshly, “N- Nii-san,
stop.”
Rin blinked before pulling away, frowning softly up at the other, “D- Did you
not like it?”
Yukio shook his head briskly as he kneeled down to be at eye level with his
brother, “God, nii-san, I loved it; it felt so good.  I would love to continue
with that, but…  I saw what you were doing earlier.”
Rin flushed softly, “Y- You saw?”
Yukio nodded, “I saw you pushing your tail into here.”  He indicated the area
that he was talking about by trailing a hand down his brother’s back to press
the tip of a finger against the previously abused hole.
Rin whimpered as he clung to his brother.
“Did it feel good?”  Yukio asked.
Rin nodded, panting softly as Yukio slowly pressed one finger passed the tight
ring of muscles that guarded his most sensitive area.
“Would you like me to touch you here more?”
“Yes, please Yukio.”  Rin pleaded; he was so hard again; the aching that he had
felt before had returned and he wanted nothing more than to let his younger
brother help him heal the ache.
Yukio removed his finger from his brother and stood, fully removing his shirt
and tossing it to the side before leaning over and taking his pants and boxers
off the rest of the way, tossing them to the side with the rest of his clothes.
Rin stood as well, watching his brother reveal his nice, slightly muscled body.
“Get on the bed, nii-san.”  Yukio instructed as he reached up to remove his
glasses.
Everything became slightly blurry for the younger boy and he was slightly
saddened that he wasn’t going to be able to see his brother very well any more,
but he knew that keeping his glasses on was just going to be unpractical.
Rin sat down on the edge of his bed and waited for Yukio to place his glasses
on the desk and join him at the edge of the bed.
Rin knew that Yukio had a lot of trouble seeing once his glasses were off so he
grabbed the other’s hand once he could reach it and helped guide the taller boy
onto the bed.
Yukio allowed his brother to guide him onto all fours over the other.
“You okay Yukio?”  He asked softly.
“Yeah.”  Yukio muttered softly back as he held himself over the smaller boy; he
stared at the other boy’s face; they were close enough that he was able to see
the features of the other boy’s face decently enough.
The two boys just stared at each other for a few moments before Yukio finally
leaned down and captured his brother’s lips in another kiss.
Rin moaned and reached up to wrap his arms around his younger brother’s neck
once again and pull him closer to his body.
Yukio would have been perfectly content with just kissing his older brother for
the rest of his life if it weren’t for the aching flesh between his legs.
Yukio gasped as he finally forced himself to pull away from his brother’s mouth
again.  He trailed his mouth to one of the boy’s ears, latching his lips just
beneath.
Rin mewled at the sensation, loving the feel of his brother’s mouth on him.
Yukio decided that he should speed this up a bit; he knew that he and his
brother were way too excited to take this slowly, so he carefully trailed his
hand down the other’s body until he found the little puckered hole that he had
prodded only moments ago.
He pressed a digit against the hole and was relieved to find that it slid in
without too much resistance.
Rin moaned eagerly, “Ngh, Yukio.”
Yukio clucked his tongue at his older brother, “Relax nii-san; I don’t want to
hurt you.”
Rin shook his head and groaned, “You won’t-“
The smaller boy was cut off as he let out a sharp breath; Yukio had just struck
that sensitive spot inside of him.
Yukio blinked, stilling his fingers for a moment, thinking that he had somehow
hurt the smaller boy.
“Yukio, more.”  Rin begged.
Yukio was unsure for a few moments, but when the smaller moved his hips so that
his fingers were forced further into the pliant hole Yukio realized that the
noise had been made in pleasure and not in pain.
He sped up the movement of his finger, gently pressing it in and out of the
tight hole, but after a few moments Rin wouldn’t have anymore.
“Yukio, more, please.”  He needed to feel more.
Yukio nodded numbly as he pressed another finger against the ring of muscles,
allowing it to slip in along with the other.
Rin grabbed at the sheets, moaning wantonly.
After a few moments Yukio was thrusting three fingers into the smaller boy and
he was sure that if he didn’t do something soon that he was going to explode
thanks to how enticing his older brother was being.
Yukio slowly removed the fingers, causing the boy that had been enjoying their
presence to whimper softly in protest, but Yukio hushed him as he spread the
other’s legs a little wider so that he could fit in between them a little
better.
He raised his legs and placed them on his shoulders, guiding his cock to the
now thoroughly stretched hole.
Rin gasped at the feeling of the tip pressed against his hole and nodded his
head rapidly, “Yes, Yukio, please.”  He whined.
Yukio took a breath before slowly pushing forward, pressing the tip of his
penis against the tight ring, allowing the head to press in before slowing down
even further.
The heat felt amazing and all Yukio wanted to do was shove into the other boy,
but he also didn’t want to hurt him.
Rin had other plans though.
Sick of how slowly his younger brother was insisting on moving, the smaller boy
decided to take things into his own hands.
Rin quickly pressed forward and before Yukio even knew what was going on he
found himself on his back on the mattress with his older brother straddling his
hips.
Rin moaned deeply as he pressed himself all the way down onto Yukio’s engorged
member.
“Nii-san!”  Yukio gasped as he instinctively grabbed the other’s hips as if to
control his movements a little better.
“Yukio… good…”  Rin muttered softly as he slowly raised himself only to plunge
back down a moment later.
Only moments ago Yukio had wanted to go slow to ensure his brother’s safety,
but now all he cared about was moving faster so that he could feel more of that
delicious friction.
“God, Nii-san, harder.”
Rin panted and nodded his head quickly as he sped up his bouncing, Yukio
helping him by guiding the other’s hips.
“Yukio, s- so good.”  Rin grunted, Yukio could tell that the other wasn’t going
to last much longer, but neither was he for that matter.
After a few moments Yukio decided that he wasn’t going to be able to stand the
pace they were at much longer and so he quickly pressed his older brother back
into the mattress and started thrusting into him a little harder.
Rin nearly shrieked with the pleasure that the new angle brought and before he
realized it that amazing tingling reached its peak.
“A- Ah!  Yukio!”  Rin screamed as he came, his walls clenching around the organ
still moving in and out of his body.
“Nn, nii-san.”  Yukio grunted in return; he had been close enough as it was,
but with the added pressure he was a goner; he came hard into the other.
Yukio collapsed onto the slightly smaller male and the two of them stayed like
that for a few moments, both trying desperately to catch their breaths.
After a few moments though, the afterglow seemed to wear off and the younger of
the two teens regained his senses.
He shot up from the other, pulling his now flaccid cock out of the older male
and nearly scrambling away from him; he couldn’t believe himself.
He had just had sex with his twin brother.
Rin panted up at the other boy for a moment before realization dawned on his
face as well.  He leaned up on his elbows and looked at Yukio.
The two of them stared at each other for several long moments, neither knowing
what to say to make all of the go away.
What were they going to do?
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