Archive of Our Own ^beta

Chapter Text

She had been a bit too distracted with the TV, not even noticing the vanishing of her brother from the living room until commercials interrupted her cartoon and she turned around to an empty couch.

Normally Rinne would be sprawled right there, a cold beer in hand as he absentmindedly stared at the tv.

Maybe he had gone for another beer?

Getting on her feet, Hiiro fixed her skirt before making her way to the kitchen. Just one look enough to confirm her brother wasn’t there, she turned around and this time tried looking in the bathroom.

She knocked twice and then pushed the door open.

Empty as well.

A hand moving up to her mouth as she tried to think of places her brother might be at. Feeling a tiny bit like the detective in her cartoon she wandered around the house.

Finally, she got to his room. The door was a bit heavy, so she had to make some effort to open it…

Rinne was there. Laying down sideways on the bed, his back turned towards the door. Headphones on he seemed to be watching some sort of video.

Her socks barely making any noise over the wooden floor, she skipped towards him, climbing the bed and kneeling right behind him, blue eyes peeking from over his shoulder.

“Nii-chama! Found you!” she declared with a proud smile, and he turned his head towards her, a faint glint of surprise in his face “What are you watching?”

She asked, bending forward to get a better look of his screen.

“Oh, you’re curious lil sis?” he asked, a grin painting his features. Before she could reply anything, he reached forward with the same arm that was holding the phone, his elbow catching on her tiny waist like a lasso, and quickly throwing her down to the bed.

A cutesy yelp, she found herself laying on her side too, her back pressed against Rinne’s warm chest as he kept her hugged close to his body. Moving somewhat clumsily, Rinne shook the headphones off his head and took the plug out from the phone, still using only his left hand.

How weird, she thought. Wouldn’t it be easier to just use his other hand? However, Rinne’s right hand was somewhere below… she tried to peek down but the harmony of loud whimpers and moans that came from the phone surprised her, blue eyes darting up at the screen.

In it, a pretty lady laid down on a bed, legs open and no clothes on… a man moving over her roughly.

Hiiro gulped, tensing up at the strange video before her eyes. She had never seen anything like it, the unusual sight so odd she couldn’t help but wanting to run away. She squirmed in her brother’s grasp, lightly kicking her feet, and wiggling around, but Rinne’s strong arm remained unmovable, holding her tightly against himself.

“Hiiro-chan? Whatcha doing? Ya wanted to see Nii-chama’s video right? Then look at it” he commanded in a playful tone, his warm breath hitting her ear as he leaned just a bit closer to her.

“B-but nii-chama… S-she looks like she’s in pain” she finally spoke up, stuttering a timid comment in hopes that would get her off the hook.

“Kyahaha! That’s cute the cute comment, sis” Rinne cackled, nuzzling her head from above as if trying to get her to look at the screen again. His voice sounded a bit odd… his breathing hot and ragged against the top of Hiiro’s head… A wet sound reaching her ears from somewhere in the room… “She ain’t in pain. She is having lots of fun~”

It really didn’t look like ‘having fun’… but she had no reason to doubt her brother’s words. He was very smart and knew about everything – that’s what their parents always said-. Of course, he must be right about this too.

Timid blue eyes stole a few more glances at the phone’s screen. At the lady that kept wailing and at the guy that was bouncing over her… a sudden change of angle making her stare right into their crotches, seeing something really big and hard going in and out the lady’s hole…

It was scary to see, and yet, her blue eyes remained glued to the sight before them. Her mind trying it’s best to wrap itself around what she was seeing. She knew her big bro had one of those big, meaty rods, even if she had never seen it looking so hard, and she knew she had a small hole between her legs…  even when the camera changed again to focus on big breasts bouncing back and forth, her mind was still caught in the previous image.

For Hiiro, the sudden raggedness of Rinne’s breathing came as a surprise, his loud heartbeats pretty evident against her back… getting just a bit worried about him Hiiro turned around as she could and threw a glance up at his face. He seemed really agitated!

“N-nii-chama? Are you okay?” she called out-loud, nervous at the inexplicable sight before her.

“Hahh… y-yeah, I’m fine” he replied half-heartedly. Lifting her closer to his face with the arm around her waist and nuzzled the side of her neck, kissing at the tender skin there.

It was weird – wet and warm and weird. His tongue lapping along the crook of her neck and the nose rubbing right against her ear, it made her squirm… and it made the feeling of tickles in her belly even worse.

“Nii-chama… t-that’s weird” she complained, her small heart beating so fast and loud her face was completely red by now.

Rinne didn’t listen, continuing to desperately lick at her -adding some nibbling and kissing to the mix-… and then his whole body tensed up, a low groan against her neck before his whole body collapsed.

“Nii-chama?! W-what’s wrong?”

Confused and rather worried for her brother, Hiiro turned around with pleading blue eyes, merely managing to get face to face with him before the strength returned to that arm, hugging her ever so warmly.

“What those teary eyes for, mn?” Rinne laughed tiredly, pressing a kiss against each of her cheeks and rubbing his forehead against hers “Nothing’s wrong sis… I’m in heaven right nooow”

He purred, hoisting her even further up to continue kissing her small face, slow and lazy. The phone now dropped to the bed; his big hand was gently caressing her tiny body, kneading at the baby fat still around her hips.

She liked this better. Being tenderly dotted on by her brother, with kisses and warm hugs. Her worries slowly melting away with each new kiss – one to her forehead, one to her cheek, one to her nose, one to her other cheek…

“Y-you really okay? Like, okay, okay?” she somehow managed to ask, eyelids falling over her eyes as she relaxed under his kisses.

“More than okay” he replied, the kiss that seemed aimed to her cheek falling tenderly over her lips. A small surge of electricity making her shiver pleasurably in his grasp “Super okay”

“R-really?” she asked again, puckering her lips as if wanting for another kiss.

“Yep, yep.” He replied playfully, leaning down to give her the kiss she wanted. Soft and short, right on her puckered lips.

A few more kisses later, Rinne sat up on the bed, moving her so she’d be standing on the floor by the bed.

“There you go. Now go watch your cartoons again, Nii-chama is going to the bathroom first” he proposed, and she nodded slightly, turning away and towards the living room.

The doubt was still there, however… curiosity slowly crawling up her body…

Chapter Text

It seemed simple enough.

Niki had his back turned to her. His full attention on the stove, as he finished preparing breakfast.

It smelled so tasty she could feel her tummy rumble!

Which meant, her big brother surely must be even hungrier.

He’d arrived home not too long ago, zigzagging his way into the hall and yelling for Hiiro and Niki to greet him.

Niki hadn’t been too happy about it, keeping Hiiro from hugging his brother as ‘the stench might get to her’: a displeasing mix of scents, from which she could only recognize a few – beer and cigarettes, and the prickly squid-like scent she sometimes caught on Rinne’s room – walking through the door along with Rinne.

Rinne had complained – loud.

He tried to push Niki out of the way, and a small altercation broke out. By the end, Rinne had been sent to take a bath, forbidden from getting breakfast, and he’d stumbled his way there, too drunk to coordinate properly.

Hiiro was smart enough to understand the ‘lack of breakfast’ was supposed to be some sort of punishment for Rinne being out of the house late at night. Still, it felt a bit excessive.

He looked pretty rough already… he surely could use a bite of something tasty!

So, yes, she thought of sneaking a couple of tamagoyaki to her brother.

The plate of warm, sweet rolls, had been left unattended on the table, just barely out of reach from her small hands. And yet, it was resting on top of the mantle – which she could grab just barely.

If she just pulled from the mantle, the plate would come closer. And the tasty tamagoyaki would be in her grasp!

Yes, it seemed simple enough.

It wasn’t.

The plate was heavier than expected, what should have been a small pull becoming anything but. By the time the plate, finally, moved from its spot, the inertia was too much – the mantle and the plate tumbling down on her.

Crack

“Wha-?” Niki turned around… to a broken plate in the floor and a small Hiiro covered with gooey egg. “Lil’ sis??? You okay?”

He rushed closer, kind and soft as ever, crouching down to be at eye-level with her.

“Are you hurt? Did the plate hit you?” he questioned, warm and gentle hands turning her around as he looked for any visible wounds. There were none.

“…S-sorry Ni-nii” she pleaded, big beady eyes looking up at him for forgiveness. Her little mischief found almost instantly.

He looked at her – a complicated frown in his face.

“…were you doing something you shouldn’t have?”

She nodded softly

“I… wanted… the tamagoyaki”

“You could have just waited a bit. Breakfast is almost ready anyway…”

“But Nii-chama…” she mumbled, little hands crumbling the soft fabric of her dress – the feeling of disappointing what essentially was like a second big-brother to her, weighing heavy on her tiny shoulders.

There was a small silence.

“…I’m just glad you aren’ hurt.” He eventually dropped in a sigh, his warm hand holding tight to her shoulder “But you shouldn’t do that. If the plate had fell on your head you’d be seriously hurt.”

She nodded again, feeling the sting of tears already appearing on her eyes.

“Ahh, d-don’t. Don’t cry lil’ sis.” He rushed to say, rubbing her arm encouragingly “Just be careful next time, yeah?”

Slightly more encouraged, she nodded again. A single sniff as she tried her best to stop the tears.

“Ah, but this is quite the problem… you got all dirty with egg” he observed, getting some pieces of the more cooked egg from her hair “You’re definitely going to need a bath… and I need to make new tamagoyaki.”

There was a small pause.

“For Rinne-kun too.” He finally said, gaining a bright smile from the girl.

His own gesture softening slightly, Niki returned to standing – a warm hand offered towards Hiiro.

“Let’s see if that bum is done showering.”

She nodded, grabbing Niki’s pinky and following him out of the kitchen and down the hall – all the way to the bath.

Rinne’s flashy clothes – leather jacket and ripped jeans, bedazzled belt, loose tank top and leopard print underwear – were all thrown carelessly across the floor, the light of the bath still on.

Niki sighed.

“Let’s get you off your clothes so you can shower, okay?” he offered, kneeling down to Hiiro’s height.

She nodded slightly, feeling a bit of annoyance left in Niki’s tone – probably towards Rinne’s lack of manners.

Big warm hands gently pulled her blue dress over her head and undid the couple of big round buttons in the front of her shirt, pulling it open to reveal soft white skin. He folded the pieces over his knee, and proceeded to take off her small socks, and finally her soft undies – detailed with strawberries.

“Rinne-kun” He called, avoiding touching Rinne’s clothes as he walked through them and towards the plastic door, which he slid open with ease.

Rinne turned to look at them, sat on the tiny plastic stool and drenched in warm water – the shower head in his right hand currently turned off. His eyes still looked a bit dazed, and his face remained prominently red.

“Huh? The fuck you want now Niki?”

“Your little sister got her hair dirty trying to steal food for you” Niki dropped with a click of the tongue.

Rinne’s frown softened, his eyes dropping to Hiiro. Niki’s hand clenched slightly on Hiiro’s, and he seemed to doubt himself for a second

“Okay, okay, I getchu~ You want me to wash lil’ Hiiro’s hair as penance. ‘s fine. I’ll do it. I’m already here and all~” his lips curved into a side smile, and he waved with his free hand for Hiiro to come closer.

There was a couple of seconds of lag – but eventually Niki released Hiiro’s small hand, allowing her to step closer into the bath.

“I’m almost done with breakfast, so you better hurry if you want to eat at all.”

“Oh, so I do get to eat? How kind of you Niki~”

“…Thank Hiiro for that.” He huffed, reluctantly retreating from the door – he still picked the trail of Rinne’s dirty clothes on his way out, throwing it into the washing along with Hiiro’s egg-stained clothes.

“Kyahah! Look at that brat, trying to act tough and all~” Rinne laughed again, eyes trailing after Niki as he returned the hose to it’s spot on the wall. His gaze only dropping back to Hiiro when Niki was out of the bathroom, the door closed behind him. “Well, let’s see what we have here…Ohh, yeah, he’s right. Like, right, right. Your hair is all sticky and gross.”

Hiiro pouted, cheeks burning bright red in embarrassment. Her shameful failure now under the scrutiny of her brother’s sharp blue eyes.

“Haha, feeling embarrassed? So cute~” Rinne chirped, squeezing one of Hiiro’s soft cheeks between his fingers – his free hand stretching forward to close the door of the shower room as well “Here, come closer, I’ll wash your hair~”

The offer sounded kind and warm. Still embarrassed, she walked even closer to her brother – he moved off the stool, offering it to her instead, so she sat on it.

Warm water soon started pouring from the shower head, falling right on top of Hiiro.

She heard a squirt, and soon enough her brother’s big fingers, lathered in the white suds from the shampoo, were on her scalp. The water was off again.

“Be a good girl and close your eyes for Nii-chama, yeah?” Rinne purred – his tone much deeper than she remembered.

Still, she closed her eyes – she’d kept them open once, a couple of months ago, wanting to be a bit rebellious for once, and the sting of the suds on her eyes were enough for her to swear off that for good.

Rinne’s fingers were really big, and warm, and gentle. He massaged her skull as he spread the shampoo, and gently went through the knots without ever pulling. That’s one thing Rinne did better than their mom.

It felt… really nice. She loved it.

“I’ll rinse it off, don’t open your eyes yet, lil’ sis” he hummed, his voice rumbling nicely in the emptiness of the bath. She nodded in agreement, her eyes shut tight.

The water started running again – warm, then slightly cold, then right back to warm.

She felt the suds being washed off her head, and down her shoulders – her brother’s kind fingers untangling her hair in the process… then sliding down to her shoulders… to her arms.

And then something soft, and warm against her shoulder.

Again… and then again…

It took her a moment to realize it was her brother’s lips, kissing her skin.

Big hands rolled forward – slow, exploratory. They traced the entirety of Hiiro’s small arms twice, before jumping forward – to her thighs. Soft circles caressed against the skin as her brother’s lips continued to pepper her back with kisses.

“…Nii-chama?” she mumbled, finally opening her eyes with disconcert – a pair of equally blue eyes greeting him on the reflection of the small mirror before them.

“Mn?” he mumbled a question, his warm voice tickling against her shoulder-blade right before his tongue would place a hot lick on the skin.

“Ngh?!” a strange sound dripped from her throat – a tingling sensation spreading across her skin where Rinne touched her.

“Hiiro tastes so good~” he mumbled behind her, his fingers sliding up from Hiiro’s thighs to her abdomen, sinking slightly into the baby fat there. “So soft~”

Another weird sound left her mouth – almost like a cry. Maybe like a sigh.

Rinne seemed pleased, his eyes glued in her reflection on the tarnished mirror – hands big enough to hide her entire stomach inching further up.

“You know you’re Nii-chama’s favorite girl in the world, right?” Rinne cooed, a hand reaching to cup at Hiiro’s perfectly flat chest.

She nodded slightly – an inexplicable warmth tingling inside her belly.

Something was… weird.

It wasn’t uncommon for Rinne to help her bath – even if the frequency of their joint showers had decreased significantly in the last year or so.

Still, she knew Rinne’s hands on her body weren’t weird.

Fingers moved again – thumb and index pinching at the pink bud in her chest a bit too hard.

“Ah!” her voice raised up, a small electric shock spreading through her body.

“Your nipples are so cute and pink~” Apparently satisfied, Rinne let go, allowing her a sigh of relief. “Nii-chama loves pink nipples~”

He hummed, fingers now moving on to massage around her nipple. Three of his big fingers more than enough to fill the space... rubbing with insistence but without much force. Like a massage.

“Pink nipples and D cups will rule the world~” A warm whisper stinking of beer hit her ear, more electric shocks making her jolt slightly in the plastic stool “I wonder if Hiiro-chan can get to D cups~”

Rinne’s other hand moved up as well – massaging the other side of Hiiro’s small chest.

“I heard breast massages can help them grow. Maybe if we start early we can even get to E cups~” he rambled about things Hiiro didn’t really understand – his words occasionally interrupted by small kisses pressed against the shell of Hiiro’s ear “That would be so hot~”

“N-Nii-chama…” she whimpered, letting her torso fall back against the strong chest of her brother, small thighs rubbing against each other – the warmth in her stomach slowly sinking lower into her body.

He chuckled – the gentle rumble spreading to her where their bodies joined.

“Wouldn’t that be good? A nice pair of E cups for Nii-chama to play with~” he continued, his voice sounding a bit more strained now.

She tilted her head up – now meeting with the direct hit of his eyes. Waiting for an answer.

What was he asking about? She had no idea…

“Whatddaya say? Dontcha want a nice pair of E cups?”

“…uh… would that… make Nii-chama… happy…?” she pondered.

His smile widened. Sweet… sickeningly so.

“Yeah, Nii-chama would be so happy~”

“Un… then… I want…” she mumbled.

She could feel the loud beat of Rinne’s heart against her back – louder and faster than ever before.

“You’re so good to me, lil’ sis~” he smiled, leaning in down. His lips pressed square against her slack mouth – the contact nice enough to make her melt further.

Rinne’s right hand left her chest, instead moving down to grab on Hiiro’s own right hand – guiding it over to her own chest.

“Here, keep massaging it yourself” he asked, his breath tasted bitter against Hiiro’s tongue

Awkward and hardly coordinated, Hiiro tried to do as she was asked. Her small fingers and soft palm trying to recreate the pressure Rinne’s fingers had provided before.

“…Nii-chama… smooch… please” she pleaded…

“Ah… fuck Hiiro…” Rinne’s breath sounded harsh, his voice a small rumble. A wet noise she hadn’t heard yet was now echoing in the bathroom “you’re so damn cute~”

She didn’t have much time to try and search for the origin of the sound – her brother’s lips once more on top of hers. Kissing, and kissing, and kissing her – his tongue rolling across both her lips, all-compassing. Overwhelming.

“Ngh… ah… H…Hiiro…” Rinne huffed against her parted lips, face scrunched tight – and something wet yet burning hot splashed against her back.

She tensed – her impulse to turn around and check thwarted by Rinne. His hand no longer massaging her chest – just pressed against it as to keep her in place.

He huffed for a moment, trying to recover his breath…

“Nii-chama… something… got on my back…” she whimpered, slightly distressed by the foreign feeling.

“Ah… it’s fine… don’t worry”

With no further answer to her questions, Rinne washed his hands under the shower head – some sticky white vanishing in the whirl on the syphon – and then washed her back as well. Hands as warm and gentle as always.

He caressed her cheek, and tilted her head backwards, big tongue slowly licking at her lips…

“Rinne-kun? What’s taking you so long? Breakfast is getting cold!”

Niki’s voice echoed through, coming loud and clear from the living room.

Rinne smiled.

“Let’s get outta here before Niki gets even more pissy~” he chuckled, ruffling her hair again and turning off the water.

Out of the shower, he reached for a couple of towels, wrapping one around his waist nonchalantly before wrapping the other around Hiiro’s body. Crouched down in front of her, he smiled with his eyes.

“Hey, don’t tell Niki about the massage, okay?”

“Mn? Why not?”

“Mn, it’s a secret!”

“…A s-cret?” she pondered, crooking her head to the right.

“Yep. We’ll surprise Niki with Hiiro’s nice E-cups in the future~ He’ll love them!”

“…he will?” her eyes sparkled.

If she could make not only her brother, but also Niki happy, then E-cups must be a really good thing!

“Mnhm. But you have to keep it a secret until then, okay?”

“Okay!”

“Kyaha! That’s my good girl!” Rinne laughed with mirth, and he leaned down to press another soft kiss against her soft lips “Nii-chama loves you sooo much~”

“I love you too, Nii-chama!” she chirped, wrapping both arms around his neck.

… sitting at the table for breakfast, changed into a pink dress, she kept kicking her legs back and forth in excitement.