Tanjiro looked down at the sleeping form of his sister, her ink black hair framing her face in the best way, the way her chest rose and fell with each breath, and the soft snores that escaped past the bamboo in her mouth. She was beautiful. She was his perfect little sister. She was his Nezuko.

Tanjiro had always been enamored with Nezuko for as long as he can remember. She had always been the most beautiful girl he'd ever seen. Her sparkling pink eyes that always had the look of warmth in them, her hair that was always pinned up but suited her perfectly, her beautiful pale skin that always glowed with the aura of love. There wasn't a thing about Nezuko he didn't love. Even now that she was a man-eating demon, he still felt the same love towards her.

All that could be heard in the small room was Nezuko's breaths and occasionally snores, but Tanjiro could also hear his heart beating in his ears. He always got like this whenever he watched his sister sleep. Something about her serene look and small noises made his heart rate rise a little.

Nezuko turned over on her side, facing Tanjiro where he was sitting on the floor next to her, still in her sleeping state. Tanjiro gazed at her, heart thumping in chest. Her kimono she always wore had slipped past her shoulders somehow, leaving them exposed. Tanjiro swallowed, his mouth feeling really dry all of a sudden. Her pale shoulders and collarbones were on show. Tanjiro felt dirty looking at them, but he also couldn't stop staring. He wanted to touch them. That was okay right? He's washed Nezuko plenty of times when they were younger and had touched them before. Besides, she was asleep, she wouldn't know anyways.

Tanjiro crawled on his hands and knees towards his sleeping sister, only able to hear the rapid beating of his heart in his ears. Once he was close enough, he took a deep breath. One touch couldn't hurt, right? He lifted his hand and grazed his fingers over Nezuko's shoulder. Her skin felt extremely soft, like silk under his fingers. He could feel her shoulder bone protruding, rubbing circles into it with his shaking fingers. He drug his fingers downwards, gliding them over her collarbone. It felt sharp but also soft. Just like Nezuko.

Tanjiro couldn't ignore the new throbbing between his legs. He felt sick. Getting hard over touching his sweet, sleeping little sister. It was wrong, he knew in his brain it was wrong. Yet, something in his mind whispered at him to keep going. That it was okay. Nezuko was asleep, she would never find out. As much as Tanjiro tried to reason with himself to stop, the voices in his head kept telling him to keep going. He swallowed.

Tanjiro's fingers dipped downwards, into Nezuko's kimono. He stopped when he felt her nipple, pebbling under his touch. He rubbed at it and twisted it between his fingers. Nezuko made a small noise in her throat, but still remained asleep. Tanjiro's heart skipped a beat. He wanted her to make more of those noises. He softly grabbed onto and squeezed her small breast with his hand. They were small enough that he could fit it into his entire hand. He squeezed it several more times, memorizing the feel in his hand. Nezuko made another small noise. Tanjiro's dick throbbed.

Everything in Tanjiro's brain was telling him to quit, but he couldn't. He was getting greedy. He needed more of his little sister. More of her body. He shakily pulled down the top of her kimono more, revealing her breasts. He dipped his head down and took one of her breasts in his mouth. He sucked at her nipple, rolling it around with his tongue. His other hand squeezing at her other breast. Nezuko writhed a bit in her sleep, making more soft noises in the back of her throat. Tanjiro whimpered around her nipple, harder than he had ever been before.

A scent wafted into Tanjiro's nostrils. Nezuko. It was sweet. The sweetest thing he'd ever smelled. It was coming from between her legs. Tanjiro lifted up the hem of her kimono, revealing her legs and panties to him. They were just a simple white cotton, but they were the most arousing thing to Tanjiro. He very softly pushed Nezuko onto her back and crawled between her legs. He put his nose right between her legs and inhaled deeply. It was Tanjiro's new favorite smell. It was so wrong and dirty, but Tanjiro couldn't stop. He got a high from.

He pressed a finger to Nezuko's panty-clad pussy, feeling the wetness that had seeped through. Tanjiro slowly slipped her panties down and off her legs, stuffing them in his pocket. He parted her lips with his fingers, and saw the shine of wetness between them. Tanjiro's mouth watered and his dick ached in his pants. He licked a stripe between her folds, her wetness coating his tongue. She tasted like honey. Like every sweet thing he's ever eaten. He never wanted to stop tasting her. Nezuko hips stuttered a bit, more noises coming from her throat. He licked harder, palming himself through his pants. His chin dripped with his saliva and Nezuko's juices. He didn't stop though. He kept licking her until her jaw ached, until his tongue hurt. His little sister tasted like heaven.

Tanjiro slipped one of his fingers inside of her, with pretty much no resistance since he ate her out for so long. She felt hot and tight inside. Everytime he slipped his finger out, her pussy pulled him back in. His dick felt like it was going to explode. He hastily pulled himself out of his pants. He sighed, thankful to be relieved of the confines of his underwear. He wanted to stroke himself, but he was scared he would cum too quickly.

Tanjiro rutted his dick against Nezuko's thigh, moaning lowly in his throat. He wanted to put it inside her so badly, battling the conflicting thoughts inside his head. The rational part of his brain told him to stop, that it was wrong, that this was his little sister he was doing this to. The pleasure-filled part of his brain, however, told him to keep going, that it felt too nice to stop, that Nezuko was asleep so she wouldn't find out anyways. In the end, the pleasure-filled part of his brain won.

Tanjiro spread her legs apart farther and hooked them around himself. He lined his dick up with Nezuko's pussy and pushed in. Tanjiro almost came instantly. His little sister was so hot, wet, and tight. Her pussy squeezed around him perfectly. Tanjiro felt like he was losing his mind, but in the best way possible. All of his senses were on fire. He closed his eyes and continued to thrust into her, uncontrollable moans slipping from his mouth.

When Tanjiro opened his eyes again, he saw two pink ones gazing back at him. Tanjiro's heart fell to his stomach. Nezuko wasn't supposed to wake up, wasn't supposed to know. Is she going to hate him now? He was her big brother, he was supposed to take care of her and protect her, not take advantage of her like this. He tried to pull out, but was stopped by Nezuko's legs wrapping tighter around him and pulling him back. Tanjiro looked down at her.

"N-Nezuko?", he asked softly, not being able to think of anything else but her name. Nezuko made her usual grunting noise and nodded. Wrapping her arms around Tanjiro's neck. Tanjiro didn't have to be told twice. Whatever Nezuko wanted, he would give her. He started thrusting again, moaning and panting above her. Nezuko made soft, high noises behind the bamboo in her mouth. Tanjiro, not thinking super clearly, moved the bamboo from her mouth, and kissed her feverishly. Nezuko returned the kiss with the same intensity.

Tanjiro's thrusts became more erratic, chasing down his orgasm. Nezuko started squeezing around her brother's cock more, getting close to her release as well. Their tongues swirled around each other, dripping spit down both of their chins.

"N-Nezuko, I-I'm-", Tanjiro whimpered. He felt like he was about to burst at the seams. He tried to pull out, but yet again was stopped by Nezuko's legs keeping him in place. He couldn't stop it, and spilled inside her, making a sharp moan as he did.

Tanjiro collapsed onto his sister, his muscles feeling like jelly. Nezuko wrapped her arms around his head, cradling him against her chest. Tanjiro could hear her heart thumping in her chest. He closed his eyes and let the beating lull him to sleep, wrapped up with his sister, the only place he ever wanted to be.