Posted originally on the Archive_of_Our_Own at https://archiveofourown.org/
works/6220255.
  Rating:
      Explicit
  Archive Warning:
      Underage
  Category:
      F/M
  Fandom:
      Charlotte_(Anime)
  Relationship:
      Otosaka_Yuu/Otosaka_Ayumi
  Character:
      Otosaka_Yuu, Otosaka_Ayumi
  Additional Tags:
      Incest, Oral_Sex, Sex, Fondling, Kissing, French_Kissing, Brother/Sister
      Incest
  Stats:
      Published: 2016-03-24 Words: 4748
****** Little Sister's Happiness ******
by orphan_account
Summary
     Yuu has returned home after his long journey, and he learns that his
     little sister has been harboring a deep secret that will impact their
     relationship.
Otosaka Yuu had woken up to a strange world, surrounded by people he did not
remember, and yet these people knew him. They included friends from his school,
one who claimed to be his girlfriend, and two siblings. He gradually learned
about them during the days he spent in the hospital recovering from his ordeal.
No matter how hard anyone tried to help, it wasn't enough to restore his memory
and nobody was sure his memory would return. It was sad to think that the
entirety of his life so far had been erased from his mind, but he could look
forward to making new memories with the people around him. When his stay in
hospital came to an end, he was brought home. His little sister had even gone
to the trouble of throwing a party in celebration of his return.
"Welcome home, Yuu onii-chan!" Ayumi spread out her arms with a massive smile
on her face.
Yuu looked around in wonder. There was a banner on the ceiling, and the table
was laden with food. A cluster of brightly coloured balloons dangled overhead.
It put a smile on his own face. He studied the faces of the people around him,
recalling their names one by one. His little sister, Ayumi. His older brother,
Shunsuke. Shunsuke's friends; Medoki, Shichino and Maedomari. Yusa and
Joujirou. Nao, his girlfriend.
"You've certainly gone to a lot of trouble, Ayumi-chan," Nao was saying.
"It wasn't any trouble at all! I wanted to give Yuu onii-chan a big welcome
home."
"You are very happy to have your big brother back, aren't you?" asked Joujirou.
"I sure am. I really missed him."
"Yeah. She couldn't wait for you to come back." Shunsuke stepped up to Yuu and
put a hand on his shoulder. "We were all missing you. It was worrying when you
disappeared, but thankfully you came back to us."
"I see." Yuu stared intently at his sister's beaming face. He could tell she
was incredibly happy to have him back. They must have been quite close to each
other, he supposed.
Everybody sat down to consume the food Ayumi had gone to the trouble of
preparing. Yuu listened to the sound of voices around him, gradually absorbing
every nugget of information that floated his way. Occasionally, he would
respond if a question was asked, but didn't say much otherwise. It was still
rather overwhelming to live in this world where his mind had become a blank
slate. He focused mainly on eating. It was a surprise to find that the curry
was so sweet and when questioning it, Ayumi proudly declared that it was the
Otosaka secret pizza sauce. To think that the family had such a thing was
bewildering.
When all the food had been consumed and it was growing late, the guests said
their farewells and departed, leaving Yuu and Ayumi alone in the house. Ayumi
settled down in front of the television and expressed her excitement at the
appearance of a girl on the television. Yuu quickly realized she was the same
girl he knew, someone in his circle of friends. Now he recalled that she was
supposed to be some famous idol, and it seemed Ayumi was a big fan of hers. It
was funny how she could get so excited seeing her on the television, when she
had been seeing her in the flesh on a regular basis. This girl certainly had
her quirks. Yuu sat down as well and watched the television along with Ayumi.
After a while of listening to How Low Hello's songs, his attention drifted to
his little sister and he smiled when he saw the enraptured expression on her
face. She really was pretty cute, he thought.
At that moment, Ayumi's mouth opened wide in a big yawn.
"Are you tired?" asked Yuu.
"Mmm." Ayumi blinked and rubbed her eyes.
"I'm pretty tired too. Shall we call it a night?"
"Okay. I'll get the futons out."
Ayumi got out the futons and rolled them out side by side. The two siblings got
ready for bed and settled down for a good night's sleep.
"Did you enjoy the party?" Ayumi turned her head towards Yuu, watching him with
a hopeful expression.
"Yeah, I did."
"Good, I'm glad." Ayumi's mouth spread into a smile. "I really wanted to do
something special for you. It was pretty tiring, but I did it. I'm glad I was
able to make you happy."
"You really worked hard for my sake, huh?" Yuu was impressed. Did he really
mean so much to his little sister? "Thank you, Ayumi."
"Ehe." Ayumi's smile widened into a grin. "I'm really glad to have you back,
Yuu onii-chan. It was a bit lonely without you."
"Was it?"
"Well, Shun onii-chan and everyone else were there for me, so I wasn't too
lonely but I still missed you so much. When I heard you'd disappeared and
nobody knew where you were, I was so worried." Ayumi's smile had completely
faded away. "I was afraid you might not come back. It was scary. But you came
back after all."
"I made everyone worry, didn't I? I don't remember what happened, but... well,
I'm sorry. I'm sure I didn't mean to do that." Yuu reached out to rub Ayumi's
head. "It's alright now."
After a long silence, Ayumi spoke again.
"Yuu onii-chan?"
"Yeah?"
"You won't leave me alone again, will you?"
Yuu wasn't sure how to answer that. He had been told the reason he left her
side in the first place. It had something to do with these adolescents who had
superpowers. He hadn't been told too much about that, but apparently he had
been one of them and it led to a mission to take all these powers away. In the
end, he had almost lost his life taking away that very last ability, only to be
saved at the last minute. Now that his mission was complete, there wouldn't be
any reason for him to leave her side again, would there? So he was confident he
could give her the answer she wanted to hear.
"I won't."
A radiant smile broke out over Ayumi's visage.
"You mean it?" Her voice wobbled as it came out. A sheen passed over her eyes
as tears formed at the corners. "You really won't leave me ever again? Do you
promise?"
"Sure, I promise."
Maybe it was an irresponsible promise, but Yuu honestly didn't care at this
point. Right now, the most important thing was his little sister's happiness.
Seeing the joy on her face was all that mattered, and he genuinely enjoyed
seeing her overcome by delight. He just wanted to keep her smiling. Seeing her
in low spirits just wasn't right. As her older brother, he would definitely do
his best to keep her happy. That was his duty, wasn't it?
"Thank goodness," Ayumi sobbed out. She pulled her body out from the covers and
crawled on top of him, putting her arms around him.
"Ayumi?"
"I'm so glad." Ayumi buried her face in his chest as she held on tightly. "I
really missed you so much, Yuu onii-chan! I don't want you to ever go away
again! I want you to stay with me all the time!" Her body shook as she let out
a series of sobs.
"Hey. Don't cry." Yuu rubbed her body, feeling it hitch with each sob she made.
"I don't want to see you be sad."
"But, I... I just missed you so much and you're finally home. It's been so
long. I've been waiting and waiting for you to come back."
Yuu felt a pang as he listened to his sister's lamenting. Had he really caused
her so much suffering in his absence?
"Umm, Yuu onii-chan?"
"What?"
"Can I... share the futon with you tonight?"
"Hm?" Yuu was taken aback by the request. "Well, don't you think it would be a
bit cramped?"
Ayumi raised her head, and he saw two damp streaks running down her reddened
cheeks. "I just... I want to sleep in your arms... can I? Just for tonight?"
Yuu supposed there wasn't anything wrong with that, and if it would stop her
tears, then he was willing to. "Okay."
Ayumi wiped her eyes and smiled. "Thanks, Yuu onii-chan." She crawled beneath
the covers of his futon and snuggled up to him. "You're so warm." With that
comment, she closed her eyes and exhaled loudly.
Yuu stared at her peaceful face, taking in the sight of her contented smile,
and felt a swelling in his chest. Though he still couldn't recall his past, he
was sure he must have cared for his little sister very much. Had they slept
together like this in each other's arms before? It didn't seem unlikely. He
felt a little sadness for not being able to remember this cute little sister of
his or the life they had lived together up until now. Thinking back, he
recalled how shocked Ayumi had been to hear he didn't even remember her and he
remembered the sadness on her face, but it had disappeared and been replaced
with a cheerful disposition so quickly. Maybe deep down, she was still
harbouring some sadness but she was doing her best not to let it show. That was
rather admirable. He vowed he was going to do his best as her big brother, to
keep her happy. With the sound of Ayumi's steady breathing resonating in his
ears and her warm body pressed to his, he soon drifted off to sleep.
"Mmm, Yuu onii-chan."
A soft moan gradually pulled Yuu from the depths of his stupor. He slowly
blinked as the fog of sleep dissipated from his mind. As he tried to ascertain
what had disturbed his slumber, he heard that breathy voice once more.
"It feels good. So good."
"Huh?" Yuu became aware of the warm, writhing form ensconced within his arms.
He recalled agreeing to share the futon with Ayumi and they had fallen asleep
in each other's arms. Could it be that she was actually talking in her sleep?
Her body was shifting and nudging against his while an jumble of slurred words
poured through her lips. He expelled a heavy breath, his lips curving at the
corners.
"Geez, Ayumi, you're keeping me awake."
What was he to do now? Maybe it would be kinder to wait for her to cease moving
and talking in her sleep, rather than wake her up. Still, Yuu really was keen
on having a good night's sleep after that tiring welcoming home party. What a
quandary he was being faced with.
"Yuu onii-chan."
"Huh?" Yuu was surprised to hear her say his name. It didn't seem like she had
woken up, so was she dreaming about him? Just what kind of dreams did his
little sister have about him, he wondered.
"I love you," Ayumi mumbled, her fingers clutching at his pajamas. "Keep doing
it to me, Yuu onii-chan... ahh... ahh..." Her breathing picked up speed, coming
out in short pants.
Yuu's brow contorted and he felt a crawling sensation on his body. Something
about the way Ayumi was speaking just seemed wrong though he couldn't quite put
his finger on it.
"Yes. That's it. Ahh. I love you so much." Ayumi smacked her lips together.
"Ayumi!" This was getting way too disturbing. Yuu grabbed her shoulder and gave
her a brisk shake. "Ayumi, wake up!"
Ayumi's eyes shot open and she stared blankly into the gloom for a while.
"Ayumi?"
"Ahh, Yuu onii-chan? What's wrong?"
Yuu propped himself up on his elbow and peered down at her face. "You were
moving in your sleep so I woke you up. Sorry, but I couldn't sleep."
"Oh. I, I'm sorry." Ayumi sat up. "I didn't mean to."
"It's okay." Yuu rubbed her head. "I know you didn't." He paused, staring at
her silhouette. "What were you dreaming about?"
"Eh?" Ayumi jumped a little. She turned her head away. "Uh... er... nothing in
particular."
"Really? It didn't sound like nothing, but if you say so."
"Sound like?" Ayumi's voice became just a little shrill. "Just what did you
hear?"
"You kept saying my name, and how you loved me, and I was doing something to
you, but I don't know what. I just thought it sounded really strange." Yuu
frowned. Why did Ayumi sound so panicked at the thought of her sleep talking
being overheard?
"Ahh... ahh..." Ayumi buried her face in her hands and started to tremble. "No,
I didn't mean to... I didn't... no... I shouldn't have... I'm sorry, I'm sorry,
I'm sorry."
"Hey, Ayumi, what's wrong? Calm down." Yuu pulled her into a tight hug. "You
didn't do anything wrong, why are you apologising?"
"I'm such a bad girl." Ayumi whimpered. "I'm a bad little sister."
"Whatever are you talking about? Just what was I doing in your dream?"
Ayumi went limp in his arms, letting out a sniffle. "B-bad things."
"Bad things?"
"I mean... like things you're not supposed to... not that you were really being
a bad person. Um... and... I... I..."
"I don't understand what you're talking about." Yuu's head was spinning, trying
to make sense of everything Ayumi was saying. Her words were only serving to
muddy the waters even more.
"We were doing things... brothers and sisters aren't supposed to do."
"Eh?"
"And I was really enjoying it. I keep having those dreams since you've been
gone, all the time." Ayumi's shoulders vibrated as she let out a series of loud
sniffles. Tears spilled forth, gliding down her cheeks in twin streams. "I feel
really bad. It's wrong to have those dirty dreams, isn't it? I'm a bad girl."
"Ayumi." Yuu didn't know what to say. He rested his chin on the top of her
head.
"Sometimes, I... I do other stuff too. I look at your pictures, I touch myself
and I say your name over and over... I even smell your clothes and take them to
bed with me, so it's like you're by my side. I'm sorry. I'm sorry. I missed you
so much. I love you, Yuu onii-chan! I really, really love you."
Yuu let go of her and clutched at his forehead. His head was spinning from the
revelation. This was all so much to take in and he wasn't even sure what to
think. This girl was his little sister and she was in love with him. Even
though he was supposed to already have a girlfriend, he had actually been
confessed to by his own little sister. He didn't need his memories to tell him
that wasn't normal. The way Ayumi was acting while confessing her sins told him
that much. He didn't know what to do now.
"Well." Yuu expelled a deep sigh. "I really don't know what I should think."
"I'm such a dirty girl." Ayumi hung her head. "I know something's wrong with me
and I'm not supposed to feel this way, but I just can't help it. I love you so
much, it hurts, right here." She clutched at her chest. "I want to be with you
so badly, I want to be by your side forever. I hate it when you aren't with me.
Yuu onii-chan." She let out a sob.
Yuu remained silent, staring into the dark space of their bedroom. He was
completely at a loss. If he said the wrong thing, he could end up hurting her
feelings and he didn't want that. He wanted to make her happy, but how could he
do that? What even was the right thing to say in this situation?
"Yuu onii-chan, do you hate me?"
"No." Yuu's answer was immediate. "Of course I don't." How could he hate this
cute girl who was his little sister? Sure, he was shocked by the things she had
said, but he definitely didn't feel anything like resentment toward her. What
did he think of her? Yuu turned his head to take in the sight of her
silhouette. He could vaguely make out her features in the dim ambience offered
by the weak light peeking through the blinds. Indeed, she was an adorable
little sister with an exuberant personality and he found it quite charming, but
at the end of the day, she was his little sister. She was out of bounds, and
besides, there was the matter of him already having a girlfriend.
"So, do you like me then?"
"Of course. You are my little sister."
Ayumi's shoulders slumped and a drawn out breath poured forth from her lungs.
"You really think of me as your little sister, even though you don't remember
me?"
The question was just too strange for Yuu to comprehend. What was there even to
think about? Her position as his little sister was a fact and nothing in the
world could change that. It was determined from the moment they were born that
they were brother and sister.
"I want to be more than just your little sister."
"Ayumi." Yuu shook his head. A dull throb steadily grew in the back of his
head. The blanket of fatigue still hung over him and he would have liked
nothing more than to return to slumber and forget all about this confusing
exchange of words. "We are brother and sister."
"I don't care!" Ayumi's shrill declaration rang in his ears. "I don't want us
to just be brother and sister! I want to... I want to..." Her voice dissolved
into a volley of sobs. "I love you. I really love you."
Yuu slowly curled his fingers into the sheets covering the lower half of his
body. He was increasingly growing frustrated by Ayumi's words. What was he
supposed to do or say? This was wrong. The subject they were discussing was an
absolute taboo, one that could surely not be breached. He just knew it was
wrong. To be in love with his little sister was a sin and he could not do that.
Why would Ayumi not understand that?
Ayumi moved without warning, throwing her body at Yuu's.
"Ayu-" Yuu's utterance of her name was muffled by the moist touch of her lips
against his. Her arms snaked around his waist and she leaned in, pressing her
lips with considerable force against his. The motion left him stunned and
unable to react from the sheer shock. It took a few seconds for him to come to
his senses and gently push her away. "Ayumi," he spluttered, "what do you think
you're doing?"
"I wanted to kiss you." Ayumi buried her face in the crook of his shoulder,
nuzzling against his warm skin. "It felt nice."
"We can't do this, Ayumi. I'm your brother. It's wrong."
"Why does it have to be wrong? You keep saying I'm your little sister, that
we're siblings, that it's wrong, and I know! I know that! But I can't help it!
I love you! I'm so tired of holding it in and pretending that I'm normal!"
Ayumi hiccuped. "Why do we have to care about people who say it's wrong?"
"Because..." Yuu trailed off, his voice giving way to a sigh. Would his words
even get through to her at this rate? It all seemed futile. Ayumi was in love
with him and his words couldn't change that fact. So what was he meant to do?
Yuu had sworn to protect her happiness and to keep her smiling. The thought of
hurting his little sister was unbearable, but could he go so far, even if it
meant committing a terrible sin? If he chose to accept her feelings, then he
would be breaking that taboo. How had he felt about her before losing his
memories? He must have cared about her. She was his precious little sister, so
her happiness must surely have been important to him back then, just as it was
now. He put his arms around Ayumi, clutching her against his chest.
"I love you too, Ayumi."
"Huh?" Ayumi pulled away to look at his face. "What did you say?"
"I said that I love you."
"R-really? You really mean that?"
Yuu's head bobbed. "Yeah. I'll accept your feelings."
"You... you really..." Ayumi's voice quivered. "Yuu onii-chan!" She flung
herself against him and kissed him once again. This time, Yuu put forth no
resistance whatsoever. If it was for Ayumi's sake, then he was willing to give
in to her desires. He really did love his cherished little sister and he would
ensure her happiness.
A gentle moan rumbled in Ayumi's larynx as she rubbed her soft lips against
his. Her hands traced along the contours of his back, slipping beneath the arms
that pressed her body against his, and came up to cup the sides of his face.
She kept her palms over his cheeks, rubbing her thumbs against his skin, and
slipped her tongue through his lips. The long, pink appendage ran over the
rough edges of his teeth and met with his own. Their moist tongues slithered
and snaked around each other in a twisting frenzy and their saliva mingled
together.
When their lips parted, they both gasped for breath, emitting heavy pants as
they stared at each other's faces.
"Yuu onii-chan... I want more... more than just kissing... I want to do it."
"It?" Yuu repeated.
"Mmm." Ayumi jerked her head up and down. She slipped her hands down to the
covers and pulled them away. "That is... if you'll let me?" She placed her
hands atop his thighs and gave him an expectant look.
"Yeah. We can do whatever you want." Yuu laid his hand atop her head and
stroked her dark locks of hair. He would allow anything his precious little
sister asked for.
"I'm glad. I'm so glad, Yuu onii-chan." Ayumi began to undress and pulled the
garments away from her body. "Please, touch me."
Yuu placed his hands against her soft, satiny skin, running them over her
slender skin. His chest started throbbing as he caressed her. When he stroked
his thumbs over the small mounds on her chest, he heard her release an
impassioned gasp. Her hands rested upon his.
"Keep rubbing me there. It feels good. Yes." Ayumi moaned as Yuu's hands
started to move in slow, steady circles, gently squeezing her perky breasts.
Her eyes closed and a smile stretched across her face. "Now, down here." She
had already removed her pajama bottoms and spread her legs wide. "Touch me
there. Put your fingers inside of me."
Yuu brought his hands to Ayumi's thighs, provoking another gasp. A quiver
passed through her body and she began to shiver with ecstasy as his fingers
rubbed over her clitoris. He cupped her between the legs and caressed her with
gentle squeezing motions, rubbing the tip of her clit and stroking the hairy
surface surrounding her labia. Her moans grew louder and she dug her fingers
into the sheets. A red bloom infused her face and her mouth gaped open as she
ululated in her mounting passion.
"Inside," she gasped out. "Put your fingers inside me."
Yuu searched around with his fingers until he discovered the opening between
her legs. It was a snug fit for his fingers though they glided through the
tunnel easily enough and quickly became slathered with her juices. He moved his
fingers around her cave, exploring the wet walls. Ayumi threw her head back and
moaned.
"Ahh! Yuu onii-chan! It feels so good!"
As her moans sounded in his ears and he felt up her moist insides, Yuu felt a
change taking over him as well. His face was warm, his blood was surging, and a
transformation was taking place down there. He was growing excited, even though
he was doing something sinful with his own little sister, and he found he
didn't care. It felt great. No longer did he care that he was committing a sin.
He was in love with this cute little girl and he wanted to keep going.
"Ahh... ahh..." Ayumi was panting, while trails of saliva dripped from her
mouth. "More... I want more... I want you inside of me, Yuu onii-chan. I want
to see your thing." She reached out and cupped his growing dick. "You're
getting hard." Her fingers tugged at his pajama bottoms and Yuu allowed her to
pull them down. She took hold of his erection and leaned down, taking it into
her mouth.
Yuu gasped as he felt Ayumi's mouth around the tip of his erection. The
sensation and the sheer exultation he felt at that second was like nothing he
remembered experiencing before. Ayumi was bobbing her head up and down, sucking
and slurping with her tongue while her hands wrapped around the base of his
hard cock. He closed his eye and basked in the throes of pleasure. After
several minutes of pure bliss, Ayumi brought her head up and wiped her mouth.
"Put it inside me." Ayumi wrapped her arms around Yuu's neck.
Yuu nodded and gently gripped Ayumi's buttocks. He lodged his erection between
her legs and thrust upward, sliding it into her opening.
"Ahh!" Ayumi squeezed her eyes shut and clenched her fists. Her entire body was
tingling with delight as Yuu's shaft slipped into her walls. She moaned and
writhed, bucking her hips and relishing the feeling of his erection within her.
Yuu thrusted repeatedly, a series of pants issuing from his throat. He hugged
Ayumi to him as he humped her. He reached his climax with a passioned howl and
unleashed his seed.
"Ahh! Yuu onii-chan came into me!" Ayumi gasped out. She could feel his sticky
load firing through her. "Yuu onii-chan!"
Yuu kept firing his load until he was completely spent. His shoulders sagged
and he quietly gasped. Ayumi gently lifted herself off him and took hold of his
dripping cock.
"I want to taste Yuu onii-chan's juices." Ayumi put her lips around the tip of
his cock and lapped at the salty residue left behind. "Mmm. Mmm. Yuu onii-chan
tastes so good, ahh." She sucked and licked until she'd had enough, then sat up
and wiped the salty traces of her brother's juices from her lips. She faced Yuu
with a broad smile. "Yuu onii-chan?"
"Yeah?"
"Thank you. I'm so happy." Ayumi leaned in to embrace him and buried her face
in his chest. "I love you so much. I've dreamed about this for ages, but I
never thought... I never dared hope... that you would ever feel the same way.
So I'm really glad. My dream came true."
Yuu smiled and stroked her hair, feeling a swell of emotion within himself. He
had broken a taboo and done unimaginable things with his little sister, but he
had made her happy and that was all that mattered as far as he was concerned.
People could say whatever they wanted but he didn't care anymore. Ayumi loved
him and he loved her.
"I love you, Ayumi," Yuu murmured, kissing the top of her head. "I'm glad I
could make you happy."
Ayumi hugged him tighter and closed her eyes, her smile widening. "You will
always be with me, won't you?"
"Of course I will. I'll never leave your side again."
"And, will you always love me? Is it okay if we do stuff like this again?"
"Yes. And, yes." Yuu put his arms around her body and hugged her. "I'll always
be there for you. No matter what, I'll make sure you're happy, so don't worry."
"Thank you," Ayumi whispered. "Hmm."
"What is it now?"
"I was just wondering. If we told people, they wouldn't be very happy about it.
I'm sure they would be angry. So, we should keep it a secret for now."
"You're probably right." Yuu opened his mouth in a yawn. "Ahh. Aren't you
tired, Ayumi?"
"Yeah."
"Let's go back to sleep, yeah? We can talk about this some more in the
morning."
"Okay." Ayumi nodded and put her pajamas back on. She snuggled up to Yuu
beneath the covers as they settled down to sleep once more. "Can I have a
goodnight kiss?"
Yuu gave her a swift kiss on the lips. "Goodnight, Ayumi."
"Night-night, Yuu onii-chan. And... I love you."
"I love you too."
With those words, they drifted off to sleep together in the snug hold of each
other's arms with smiles on their faces, feeling not shame, regret or worry,
but only sheer happiness and immense satisfaction.
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