It had been three nights since the "Hoshino Ryūto" reveal, and a new, secret rhythm had established itself in the Yuuki household.
The days were still loud. Lala would beam down from her attic lab for breakfast, usually covered in soot or glowing slime. Haruna would text Rito shy, affectionate updates about her day. Run would send selfies from her dressing room.
But the nights... the nights belonged to Mikan.
…
11:30 PM.
The door to Rito's room clicked shut, sealing out the rest of the world.
"You missed a spot." Mikan said, her voice quiet but authoritative.
She was sitting cross-legged on the floor, leaning over a low work table Rito had set up. She held an X-Acto knife with the precision of a surgeon, cutting a sheet of screentone to fit the shadow of a dragon's wing.
Rito looked up from his main desk. He was wearing his "work uniform", a loose grey tank top and boxers. The tank top hung low, exposing the deep, defined grooves of his 5-pack and the corded muscle of his shoulders as he inked a background.
"Where?" Rito asked, wiping ink from his cheek.
"Here. The cloud shading." Mikan pointed with the tip of the knife. "If you want to win that award, you can't be sloppy, Hoshino-sensei."
Rito laughed, a tired, happy sound. "Yes, ma'am. What would I do without you?"
Mikan didn't look up, but the tips of her ears turned pink.
She was wearing her summer pajamas, a simple, oversized t-shirt and short shorts that left her pale legs bare against the tatami.
For Mikan, this was heaven. No alien princesses showing off engagement seals. No idols flashing their stomachs. No shy librarians getting kissed in the archives.
Just her, Rito, and the quiet scratch of pens on paper. It was a secret world where she wasn't just the "little sister" who cooked dinner; she was the Assistant. The partner. The one who made his dream possible.
"Hey, Mikan," Rito said after a while, stretching his arms over his head. His back cracked, and his shirt rode up, exposing his navel. Mikan's eyes darted to the movement, then quickly back to her work.
"What?"
"I need the reference book for the fighting stances. It's on the top shelf."
Rito stood up. He grabbed his swivel chair, which had a broken wheel from one of Lala's earlier experiments, and dragged it over to the tall bookshelf.
He stepped up onto the seat. The chair wobbled dangerously.
"Whoa!" Rito grabbed the shelf to steady himself. "Okay, this is sketchier than I thought. Peke isn't here to hold it."
"Be careful, idiot." Mikan sighed, putting down her knife. "Do you want me to hold it?"
"Actually..." Rito looked down at her. The angle was dangerous; from up here, he could look right down the loose collar of her t-shirt. He quickly looked away, his honest nature acknowledging the sight but respecting the work mode.
"It's tipping backward." Rito explained. "Holding it won't help. I need a counterweight on the seat while I reach back for the heavy volume."
He hesitated, then looked at her.
"Mikan... could you sit? Just on the edge of the chair? Between my legs?"
Mikan blinked. "Hah? You want me to sit on your lap?"
"Just for a second," Rito said, looking flustered but practical. "Or I'm going to fall and ruin the ink jar."
Mikan looked at the unstable chair. She looked at Rito's pleading expression. She sighed, standing up and smoothing her short shorts.
"Fine. But if you fall on me, I'm making you pay rent."
She walked over. Rito stood with his legs spread wide on the chair seat to give her space. Mikan turned her back to him and gingerly sat down on the edge of the cushion, right between his calves.
"Okay," she muttered, her heart starting to beat a little faster. "I'm sitting. Hurry up."
"Thanks. Reaching now..."
Rito leaned back, stretching his arm toward the top shelf. His weight shifted. To keep his balance, his legs instinctively tightened.
His thighs clamped around Mikan's waist. And as he leaned, his hips shifted forward.
And the contact was made.
Mikan froze.
Through the thin fabric of her pajama shorts and his cotton boxers, she felt it.
It wasn't just a bump. It was a solid, heavy bar of heat pressing directly against her lower back and buttocks.
Rito's physiology, that hyper-reactive, "addictive" biology, didn't care that they were working. It didn't care that she was his sister. It reacted to the scent of her shampoo, the warmth of her body, and the sudden, intimate friction.
In seconds, Rito went from soft to fully, aggressively hard.
The 9-inch monster expanded rapidly, filling the space between them, pressing firmly into the crack of her bottom, hot and twitching.
"Ah..." Rito breathed, freezing in mid-reach.
Mikan gasped, her hands gripping her own knees. She could feel the shape of it. The thick veins. The pulsing head. It was massive.
"Rito..." she whispered, her voice trembling. "You're..."
"Yeah," Rito said. He didn't pull away. He couldn't. The chair was too wobbly. He looked down at the top of her head, his face burning but his voice low and honest. "Sorry, Mikan. It... just happens. You're... really close."
…
"You're... really close."
Rito's words hung in the quiet room, heavy and charged.
Mikan didn't move. She sat frozen on the edge of the chair, her back pressed against his chest, her bottom resting squarely on his thighs. And between them, separated only by thin cotton, was the undeniable, throbbing reality of his erection.
It was hot. Searing hot. She could feel the distinct shape of it, the thick base, the long shaft, the flared head, pressing into the cleft of her buttocks. It twitched against her, a rhythmic thump-thump that matched his racing heart.
'He's hard.' Mikan thought, her mind reeling. 'Because of me. Just because I'm sitting here.'
She knew about Lala. She knew about Run. She knew about Haruna. She had assumed Rito's desire was reserved for them, the beautiful aliens, the busty idols and other charming girls. She had convinced herself she was just the "little sister", the safe zone where his lust didn't reach.
But this... this hard, demanding pressure against her skin told a different story.
"Rito…" Mikan whispered, her voice trembling. She didn't jump up. She didn't elbow him. Instead, she leaned back.
Just a fraction of an inch.
It was a tiny movement, barely perceptible, but the effect was electric. Her weight pressed down on his erection, grinding the sensitive head against her tailbone.
"Nnngh!"
Rito hissed, his grip tightening on the reference book he had just pulled from the shelf. His other hand, seeking balance, came down to rest on her shoulder. "Mikan... don't move."
"Why?" she asked, her voice barely audible. She felt a strange, dark thrill coiling in her stomach. "Does it... feel good?"
Rito looked down at the top of her head. The scent of her shampoo, simple, clean citrus, was filling his nose, mixing with his own rising musk. He was the honest Rito now, and he couldn't lie to her.
"Yeah…" he breathed, his voice rough. "It feels... too good. If you move like that again... I might do something weird."
Mikan's heart skipped a beat.
'Do something weird.'
For a terrifying, exhilarating second, she imagined it. She imagined his hand sliding down from her shoulder to her chest. She imagined him pushing her forward, lifting her hips, and satisfying that thumping pressure right here on the swivel chair.
She bit her lip. The temptation to grind back against him again, to test just how far she could push him, was overwhelming.
'I have power over him too,' she realized. 'I'm not just the housekeeper.'
But the chair wobbled ominously under their combined weight and shifting balance.
Squeak.
The sound broke the spell.
Mikan gasped, her face flushing a brilliant scarlet as reality rushed back in. She scrambled off his lap, nearly tripping over a stack of manuscript paper.
"S-Stupid Onii-chan!" she stammered, turning to face him, her hands clutching the hem of her t-shirt. "You... you pervert! Getting... getting like that just from sitting!"
Rito stepped down from the chair, clutching the book to his chest to hide the evidence, though the tent in his boxers was impossible to miss. He was blushing, but he didn't look away.
"I told you." he said, rubbing the back of his neck with his free hand. "I can't help it. You're... you're a girl, Mikan. An incredibly cute one."
Mikan froze. Her mouth opened, then closed. The insult she had prepared died in her throat.
'An incredibly cute one.'
She turned away sharply, marching back to her low table and picking up her X-Acto knife. Her hands were shaking so badly she couldn't cut straight.
"Just... just give me the book," she muttered, not looking at him. "We have to finish this chapter tonight."
Rito handed it to her, sitting back down at his desk. The silence that followed wasn't the cold, angry silence of the past few weeks. It was thick, heavy, and humming with a tension that hadn't been there before.
As Mikan worked, she couldn't help but glance at him. He was focused on his drawing again, but every now and then, he would shift in his seat, adjusting his shorts.
A small, secret smile touched Mikan's lips.
'He's still hard.' she thought, cutting a piece of tone with renewed precision. 'He's still thinking about it.'
And for the first time in weeks, Mikan didn't feel left out. She felt like she was winning.
*****
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