Nikuyoku - Chapter Five | Commission: Chibi Chi

As Rin and Mako headed back home after their ice cream, Rin could feel Daichi moving around in her rectum as she walked. Each stride she took served to knock him into the shit covered lining of her rectal cavern. Shivers reverberated through her body with each slight knock, feelings she could neither describe nor had she ever experienced before.

Daichi was overwhelmed by the intoxicating odour in Rin’s dank depths, it was pitch black and he could hear everything from the thunderous booms of Rin’s beating heart and even the faintest constant roar that he guessed was her stomach. Blindly, he made his way towards her sphincter; tripping over the ribbed lining of her rectal cavern and covering himself in the excess faeces that still lay within.

As Rin and Mako made light conversation, she could feel her legs getting shaky and her breaths increasing in frequency. Her face flushed red and Mako noticed, “Rin, are you feeling okay?

“Yes, Grandpa. I’m just a little hot!” Rin replied, fanning her face. She tried to play it cool as she felt Daichi traversing the ridges of her rectum towards her sensitive sphincter. Reaching it, he began to caress the edges in morbid curiosity. Immediately feeling this, a sharp moan escaped Rin’s lips suddenly as Daichi touched what he should not, but she managed to stifle most of the noise before Mako would hear much more than a fraction of a yelp.

In an attempt to stop her ill-behaved brother, Rin shook her ass sharply in a stomping motion to try and dislodge him from his current position. She felt his tiny body tumbling deeper into her rectum. As Daichi fell further into the depths of his sister, he eventually came to a stop against a wall of sludge and felt his arms sink in.

Tugging at them, Daichi found he was totally unable to get his arms out. His movements only seemed to move him deeper, so he remained still; his face mere inches away from the huge mass. A deep rumble vibrated through Rin’s body, followed by the huge wall of shit chugging it’s way towards Daichi bit by bit and swallowing his arms up further to just below his shoulders. The oozing mass dripping menacingly down onto him. 

Unable to hold his breath anymore, Daichi finally gave in and inhaled. The smell was the most potent, vile concoction he had ever had to breathe. A combination of sulphur and rotting carcasses invaded his senses. He certainly wasn’t surprised, he was face to face with a mound of shit so large you’d only expect it in the pits of a sewage plant.

The smell was… intoxicating, he couldn’t help but be intrigued as his penis sprung to life. This was a strong confliction in his mind that he hadn’t felt since he first had those strange feelings. Rin’s shit was horrific, it was nasty, atrocious, foul, odious. So why did he love it so much? What had happened to him? 

As Rin approached the house, she couldn’t really feel Daichi inside of her anymore; although she knew he was certainly in there as she’d feel him leaving. The pressure in her rectum had increased, she could feel her stomach churning up the meals she had eaten today. 

Rin’s massive, brown log chugged along her rectum further. Daichi could do nothing as it slowly engulfed him, taking in his shoulders and head. It didn’t take long until he was completely enveloped by her waste as it carried him towards her sphincter. Rin could feel it getting closer and closer to her backdoor before finally pressing against it, she wondered where Daichi was if her poop was filling all that space? One thing was certain, she was desperate for the toilet.

Hurrying into the house, Rin thanked her grandfather for the ice cream and rushed upstairs to the bathroom. Mako watched as she frantically threw herself up the stairs like some sort of jackal. He smirked to himself, “That girl can be quite the enigma sometimes”, and headed into the kitchen for some tea.

Slamming the door shut behind her, Rin removed her panties and jumped on top of the toilet, allowing the flesh of her ass to sink into the bowl slightly from the force of landing. She knew Daichi was somewhere deep inside of her but there was still only one thing she could do. Straining, she attempted to push the huge log out in hopes of relieving the pressure in her butt, but also finding Daichi. She felt the girthy mass slowly edging it’s way out of her and further into the bowl.

Daichi could feel his brown prison moving, although he couldn’t tell if he was still inside Rin’s rectum or not. His thick, sludge-like surroundings allowed no light to pass through and most sound didn’t make it either. Suddenly, Daichi felt weightless for a moment before immediately feeling the icy cold water of their toilet seeping in around him; causing the faecal matter encasing him to begin to break apart.

Rin, not even thinking that Daichi might be in that initial log, continued to use the toilet as normal. She strained once more, causing a wet fart to slip out. The toilet bowl caused what would’ve been quite a quiet fart to turn into a loud, bassy trump - nearly bursting Daichi’s eardrums as it echoed around the bowl.

Suddenly, a blast of hot, steaming, yellow urine burst out of Rin’s vagina and into the toilet below. The powerful jet lasted what felt like an eternity for Daichi, it ripped apart his faecal prison and continued to hit him; plunging him deep into the murky water. He desperately clambered towards the surface but the strong current continued to push him under upon each attempt. 

Finally finished using the toilet, Rin stood up from the toilet without wiping so she could inspect the bowl more thoroughly without toilet paper in it. It looked like a normal toilet with poop in. Suddenly a brown figure floated up and a tiny fountain of brown water sprayed upwards as Daichi coughed up some water from his lungs. Rin could barely even make him out in the brown-yellow water as he was covered in her waste.

With an understanding of where Daichi was now, she wiped her ass quickly with a few sheets of toilet paper. Carefully she dropped the sheets onto the side of the bowl, hoping to not cover Daichi at all with the poop stained sheets so she could avoid having to dig around to get him.

Finished wiping, she reached into the bowl and carefully plucked him out, unable to keep her hand clean as she did. A little disgusted by having to touch her own excrement, Rin carried him over to the sink and threw him into it, wanting to wash her hands as soon as possible. She turned the tap on and the jet of water blasted over her hands before washing over Daichi’s shit covered form.

He lay there, enjoying the soapy water covering his body. He tried his best to keep his head above the water, thankful that Rin’s hands took the brunt of the blast from the tap. Reaching down, Rin grasped Daichi from near the drain and began to rub his body clean. Daichi was in bliss as the pads of her soft fingers grinded against his tender skin.

His bliss was short lived as Rin soon turned the tap off and carried him over to a towel. Carelessly, she rubbed his puny body with the coarse towel until he was relatively dry. Daichi felt a little sore, the towel at his size wasn’t exactly smooth. Rin flushed the toilet and headed out of the bathroom.

Making her way into her bedroom, Rin shut the door with her spare hand and made her way over to her bed. Climbing onto her soft duvet, she placed her brother between her legs. They stared at each other for a long time, remaining in silence for the entirety of the stare. Rin wanted something but she didn’t know how to ask. Would he do it? Would it matter if he wanted to? He was hers now after all and she wanted him between her cheeks, to massage her butthole.

Plucking Daichi up into the air without explaining why, he watched as her entire body rotated until she was laying on her front. Moving her hand behind her back, she dropped the tiny Daichi onto her back. Daichi, confused, looked up towards her face as she twisted her neck to face him standing on her back.

“Get in”, Rin said simply, her voice void of emotion. Get in? Daichi didn’t understand. He looked around and saw nothing to get in. Impatiently, Rin reached towards him and Daichi expected to be plucked up. However, Rin’s hand continued down towards her waistband and she pulled it away from her body to reveal her bare cheeks.

She couldn’t mean it, could she? He understood why she did what she did when they went for ice cream but this was a whole different level of on purpose. Hesitating, Daichi turned back towards his stoic sister’s face and waited for some clarification. The only clarification he received was her fingers gently tapping his back, causing him to stumble towards the inside of Rin’s panties.

Daichi wasn’t totally opposed to this venture. He had both loved and hated his earlier experience between her cheeks, with each passing time serving Rin he was slowly beginning to appreciate it more. As he crossed over the line where her waistband had pressed into his skin, he noticed how much less light there was in here.

Daichi continued on through the valley between Rin’s cheeks. Soon reaching the area where he’d have to dig down to get to her sensitive sphincter, he took a deep whiff in. The odour was as potent as it had been when he’d had her head in her ass, much worse than when he was just between her cheeks earlier.

With all his might, Daichi spread Rin’s cheeks apart and peered down into the depths of her crack. Looking back towards the light, he was met by Rin’s hand descending into her panties. She pushed Daichi again, slightly harder than before, and he was sent tumbling into the depths of her crack.

Daichi screamed as he fell into the depths of Rin’s crack.The smell, whilst her cheeks were relatively clean, was potent. Surrounded by her cheeks, he looked up to see Rin’s index finger accurately beaming down on him. He could do nothing but watch as her finger pushed him until he met her asshole and came to a stop.

Rin’s finger left as soon as it had arrived. The light soon faded as Rin allowed her waistband to snap shut, leaving her brother in the darkness. Daichi’s erection was rock hard and he couldn’t ignore it anymore, it felt so wrong yet so right. Everything he had learned up to this point had taught him that this entire situation was horrific, yet he had these indescribable feelings. Slowly, he began to work his hard penis into a powerful and rhythmic masturbation. 

Rin waited for what felt like an age for Daichi to do something, she ached for his touch. Temptingly, she flexed her butthole on him but could feel nothing but very slight movement against one of her cheeks. What was he doing? She continued to wait patiently, although her patience was wearing thin.

Daichi was in bliss lying between Rin’s cheeks. He felt amazing as he jerked his penis faster and faster, the foul odour only serving in making him more turned on. After ten minutes of intense masturbation, he felt his body edging its way towards climax. Just a few more pumps.

Bored now, after having lay there waiting for him, Rin decided enough was enough. She was impossibly horny and wanted more than him just to lay there, so she’d have to do it herself. Keeping her hand on the outside of her panties, she slid her hand into the back of her pants. Pressing down towards her butthole, her panty-covered fingers soon met Daichi.

She moaned lightly as she began pressing him into her hole, her panties’ soft fabric soothed her as they brushed against her cheeks. Daichi could do nothing as Rin’s panties pinned him down to the odorous hole. He felt deja vu as he felt his body sinking into her sphincter, only this time she was forcing his entire body in.

Daichi screamed out as his sister cut his masturbation just short of climax. He was extremely frustrated and could do nothing about it as she pushed him deeper into her asshole. Her prying fingers pressed against him harder and harder, threatening to push him past her elasticated flesh and back into her rectum. He was desperate for release but couldn’t even reach his penis as his arms were pinned to his her sphincter by her powerful finger.

Stopping just short of pushing Daichi fully in, she began to sensually rub her panties against her butthole in a circular motion. It was euphoric, she had never realised how amazing this could feel. She barely even considered the situation Daichi was in, even forgetting that it was her brother between her cheeks and not a toy. Although, even the times she remembered it was him she was enjoying the feeling too much to care.

Daichi screamed out in pain as his body was crushed against his sister’s anus as she masturbated it. He thought back to how she had wanted him between her cheeks and he had used that time to masturbate himself. As her moans rumbled through her body, he realised what she had wanted him to do and regretted not giving her what she wanted. He was at her mercy now.

Feeling more and more pleasure with each moment that passed, Rin’s high pitched moans became louder and more frequent. She rubbed her anus through her panties harder and faster, the increasing pressure causing her to feel immense euphoria. Ripples of pleasure coursed from her sensitive sphincter and right up her back to her neck.

She could feel her body beginning to contract and her toes beginning to curl as her fingers circled around her butthole, and Daichi. She could feel him slowly sinking deeper, her hungry butthole kneading his body between its creases as she rode the amazing feeling. She pressed her fingers into her ass even harder as she tried to stifle a screaming moan, causing Daichi to sink in even deeper.

His body was contorted in such a way that the only things remaining outside of her sphincter were his head, arms and legs. He could only lay witness to his sister’s intense anal masturbation as her panty-clad fingers rubbed across him and his prison constantly. With each passing moment, he sank slightly deeper until his head was sucked in.

Reaching her climax, Rin screamed out and forced her fingers as deep as her panties would allow into her asshole, forcing Daichi into her rectum completely. He fell into her now empty rectal cavity at the ideal moment for the walls to come bone-crushingly in on him as her orgasm coursed through her. He screamed out as the high pressure cavern caved in on him, causing her slick walls to squish his tiny body. 

With her breaths heavy and slow now, Rin tiredly left her panties wedgied into her crack as she removed her prowling fingers and lay in a heap on her bed. The euphoria from her masturbation didn’t leave her, she was in a state of exhausted bliss. The last thing on her mind was Daichi, and even if she remembered him, why would she need to care?

Climbing under her sheets slowly, she pulled them over her clothed body and fell into a deep sleep. Not waking up until the following morning after having slept for fourteen hours with Daichi in her rectum.

Hours passed that felt like weeks. Inside of Rin’s rectum for such a long time with no movement or sounds from Rin, other than the thumping beat of her heart and the rumbling of her digestive system, Daichi felt himself slowly going insane. He was completely surrounded by her waste as it slowly filled her rectum over the fourteen hours.

The smell became more and more intense as it filled the cavern he was trapped in. He was still extremely turned on from his previous masturbation session, his balls had never been more blue from Rin cutting it short. Eventually, from a combination of boredom and lust from his new interest in her odours, Daichi continued to masturbate.

As he approached orgasm, Rin rolled in her sleep and Daichi fell into the wall of faecal sludge that slowly made its way along her rectum. He screamed out in surprise, causing her stinking waste to get into his mouth and onto his tongue. The pungent tang covered his taste buds just as he ejaculated, after having waited so long to do so. The positive association with the sour, rotten taste of her shit awakened the flickering lust towards all things Rin, including her waste.

The night was a life changing experience for Daichi. His conflictions were no more. He had initially been torn by what he was enduring, even hating the moments he was violently being smeared across his sister’s shitty asshole. It seemed to last an age and his skin was extremely sore from the abrasions.  

Topped off by being forced into her asshole before an abnormally long sleep, he was forced to endure her body’s entire digestion process for the fourteen hours he was in there. He came out of it an entirely changed person, as Rin would come to realise. What had previously just been very slight interest in her and her waste, that he had tried to ignore, was now a burning desire. He was no longer her brother, he was hers. He was no longer torn by the smells and tastes of her excrement, but rather turned on by it to no end.

Similarly, Rin would wake up realising she had a thing for anal. And the brother she had used in only caring and safe ways up until recently, was about to be subject to a lifetime of sexual abuse, whether he liked it or not. Luckily for him, he was ready to enjoy it. However, Rin was ready to see just how far he could be pushed.