Makoto's fist pounded against the door of Komaru's bedroom, almost but not quite overpowering the lewd noises coming from the other side. "Komaru! Komaru!" He shouted. "What are you doing!?"

Komaru didn't answer, hoping he would open the door himself as she laid naked on her bed, sliding her finger in and out of her wet pussy, a feeling she'd discovered she really liked since her brother had shown her those lewd things a few weeks ago.

The door creaked open and a strong blush grew over Makoto's face as he saw what she was doing. "Hey, stop that!"

"Makotoooooo…it feels so good…come in-ahhhh!" Komaru moaned as she begged for him to come inside.

Makoto stepped inside, but his resolve refused to waver. "Stop that right now! It's…it's not right!"

"M-Makoto! I want…I want to do it again. Do the lewd thing…with your thingy! P-please?"

"Absolutely not! That was a big mistake! Just...forget about it, please?"

Komaru's body lurched as she reached a climax, though she didn't know that's what it was called. "Makotooooo!" She moaned as a few juices leaked out of her developing body. Makoto spun around and bolted from the room as he saw his sister orgasm, guilt and shame overriding how lustful he was as he did so. "Makoto! Wh-why are you running away?!" She called after him.

"Leave me alone! And stop that!" Makoto shouted behind himself as he ran to his room and slammed the door shut.

As Komaru looked out into the hallway, towards Makoto's room, she pouted, and flopped back onto her bed, still slightly panting. She looked down at her nude form, and thought of her brother, and how it had felt when he did that thing with her. She wanted more…so badly. Somewhere deep inside she knew it was wrong somehow, but she didn't care. But how to convince him?

As she looked down at herself, an idea popped into her head. Their parents wouldn't be back until Monday, and seeing her naked seemed to trigger him. That's how she'd do it! With a smirk, she got up off the bed, her legs wobbling a bit as she walked over to his door, and knocked. It felt weird to be naked outside of her room, but also…kind of exciting!

"Go away."

She ignored that and knocked again.

A loud sigh was heard, and after a few seconds, the door opened. "Komaru, put some clothes on."

"Not until you do that thing again~! What's it called anyway? You never told me." Komaru said, sticking out her chest as much as she could, seeing him trying hard not to look.

Makoto hid behind the door slightly. "Sex, and it's not something you're supposed to do with your brother!"

"Sex!" Komaru exclaimed with a word as she pushed against the door. "I wanna do sex!!"

Makoto pushed back with the door. "Absolutely not, Komaru! It was wrong, and I'm sorry, but you need to let it go."

"Whyyyy?" She said, pushing back harder.

"Because it's wrong! Now just leave me alone!"

"No!" Komaru continued to shove against the door.

Makoto gave one last great push to the door, sending Komaru sprawling to the floor. Before he retreated back inside, he got one good glimpse of her pussy, still wet from her...activities. A glimpse that wouldn't leave his mind long after he had turned on the TV and tried ignoring her from the other side of the door.

Komaru stood up and rubbed her now slightly sore butt, and huffed as she walked into the living room and angrily plopped herself down on the couch. She jumped for a moment as she felt the couch against her bare skin, and felt the urge to get dressed but she was determined to stay naked! So, she grabbed the remote, and turned on the TV. However, she had a hard time paying attention as she continued to shift around.

Makoto, back in his room, was wracked with guilt. This whole situation was his fault. Him and his stupid hormonal brain. The knowledge of that tore him apart, but what to do to make it better?

Unknowing to Makoto's guilt, before she knew it, Komaru was touching herself again, rubbing her hand against her pussy, moaning at the tingle she felt spreading across her body.

Makoto cracked open his bedroom door and tip-toed out, resolving to apologize to Komaru, this time without the judgement.

Komaru wasn't sure why, but her free hand found its way up her body to her chest, where as soon as she touched her budding breasts, she moaned again, her body shuddering.

Makoto couldn't find Komaru in her room, and so he made his way to the stairs and began his descent.

She poked one of her nipples and it took her breath away with how amazing it felt. After that, she rubbed the hard nub with her finger as she inserted a finger inside herself again.

Makoto rounded the corner of the stairs and there was Komaru, masturbating again. This time, with how much calmer he felt, there was something different about it. He was frozen in his tracks because it was...beautiful?

Unaware of Makoto staring at her, she lost herself in her pleasure as she thrust a finger in and out of herself as she continued to rub her nipple. With the extra stimulation on her breast, she came much faster than before, squirting out more juices onto the couch, her body arching before falling back down. As she panted, she knew she'd need to clean up, so after a few moments, she stood up, and started walking to the kitchen to grab paper towels, still unaware of Makoto even as he stared at her butt as she walked away.

"K-Komaru I-"

"EEEEK!" Komaru jumped, whipping around towards Makoto, defensively holding her hands up. "H-huh? Were you…watching me?"

"I-" Makoto inhaled. "Yes."

Komaru giggled as she ran up to him and hugged him, pressing her nude body against his clothed one. "Perv~!"

Makoto froze at the feeling of her pressing against him. She was so soft, so warm, so- "Komaru I just...let go!"

This time, she did as she was told, and let go, turning back to the kitchen to get the paper towels. But, before she left the room, she looked over her shoulder at Makoto, and shook her ass, giggling.

Makoto looked down at his crotch after she left, confirming the sizable tent she was just rubbing against. This was going to be...harder than he thought.

Komaru stared at Makoto as she was eating her cereal, still naked. She was so focused on him that when she brought the spoon up, she missed, bashing it against her chin and causing the milk to spill onto her chest.

Makoto stifled a chuckle. "Regretting not wearing a shirt yet?"

Komaru pouted, and shook her head, instead puffing out her chest as much as she could, holding her breath to do it as she stared at him.

Makoto's eyes shot down to her chest. Was it just him or did the milk remind him of-

"Here," Makoto sputtered as he thrust a paper towel across the table. "Wipe yourself off."

Komaru bent over as she stood in front of the couch, right in front of Makoto, slightly shaking her butt as she did so.

"Komaru, I'm trying to do homework..."

"Sorry, just stretching." She lied as she turned towards him, and put her hands on her back as she leaned back, sticking out her chest.

Makoto looked at his hands and realized they were shaking. And there was a familiar stirring in his pants- "Can't you do that in your room?"

"Nope!" She said, and stretched to either side, her small chest jiggling slightly with her movements.

Makoto let out an exhale. She didn't need to know he was going to masturbate to this later, but how much longer could he last?

"Makoto! Makoto! I need your help with something!" Komaru shouted as she ran into the living room, clothed for the first time that weekend.

Makoto smiled at her. "What is it?"

She produced a camera and handed it to him. "I need you to take a few pictures of me. For a class."

Makoto grabbed the camera and looked it over. "What kind of pictures?"

Without a word, Komaru smiled as she quickly stripped down the clothes she'd put on just for this, trying to be as seductive as she could as she did it.

"K-k-komaru!?"

Naked before her brother once more, she smiled and struck a pose for him, winking.

Makoto sheepishly raised the camera, barely, and snapped a photo of her feet on accident.

"Not my feet!" She exclaimed.

"Ko-ko-komaru, I don't think I can-"

"Don't think you can what~?"

"Take the picture..."

"Why not?"

"Just put your clothes on!"

Makoto tossed and turned a bit in bed, eyes firmly closed but mind racing. All he could think about was Komaru, all the time these days...

Komaru quietly slipped into the room, and, still just as naked as she'd been all day, crawled under the covers and snuggled up to Makoto as quickly as she could, wrapping her arms around his front as she pressed her breasts against his back.

Makoto jolted as he felt her press against him. "Komaru!" He hissed. "What are you doing!?"

"Sleeping with you~!"

"Get out of my bed!"

At that, she snuggled up tighter, one of her arms bumping up against his crotch.

Makoto sighed. "If you try anything funny, I'm putting ants in your shampoo tomorrow."

"No you won't!" she said with confidence as she snuggled her head against him, and closed her eyes, smiling.

The summer vacation started with a road trip to a ferry to Hokkaido. Makoto sat against the car door, windowgazing at the Japanese countryside.

"It's weirdly pretty." Komaru said as she looked out the window.

"We live in a pretty place," Makoto idled. "The rolling hills, covered with their crawling trees, moss dripping from the branches as the last vestiges of spring give way to summer. A time of great change and even greater beauty."

Komaru couldn't help but laugh at his little speech as she glanced down at his crotch, then at their parents. They didn't seem to be looking, so she reached over and placed her hand against his crotch, and gave it a slight squeeze.

Makoto squeaked and kicked, accidentally sending a foot into his mom's seat.

"What was that!?"

"Sorry, Mom!" He sputtered. "I, uh, twitched. I'm...really cramped."

"Don't worry," their dad interjected. "We're almost to the motel."

Makoto shot a glare at his sister as he readjusted in his seat. Komaru smirked, and as soon as they looked away, she did it again, happy to find it felt a little harder than before. This time Makoto simply drew his knees up to his chest and grabbed her wrist, hard enough that his fingernails left marks in her skin.

Her eyes twitched from the slight pain, but she didn't give in, and instead twisted her body so her other hand could go over and go so far as to wrap her hand around his cock through his pants.

Makoto's eyes widened in horror, but he wouldn't give in. He released her arm and used both of his hands to push her back, the problem being that as he did so, both of them groped her budding chest in the process.

"Ahhh~!" Komaru moaned.

"What was that?" Their mom asked.

"Nothing," the siblings said in perfect unison, before Makoto glared back at a smug Komaru.

Makoto lazed out on the living room couch, watching some documentary on the TV. Komaru was perched up on the couch, frantically typing away and browsing on her phone.

Komaru glanced over at Makoto and smirked as she hit the send button.

Makoto sighed as his phone vibrated away in his pocket. He dragged it out, clicked on the notification, and was assaulted with fanart of Sora and Shiro, the protagonists of his favorite anime, 69'ing.

"Komaru?"

"Yeah?"

"You sent me the wrong thing...whatever it is you were trying to send."

"Oh sorry! Let me try again." She said as she sent the "right" picture.

This time Sora was on his knees, dragging his tongue across Shiro's clit. "Komaru, what is this?"

"Something I thought you'd like. Or maybe give you ideas~?"

Makoto was used to her tricks, he thought, and he knew the counter. He simply shrugged and smiled. "Nice try, not interested."

Komaru pouted, and as a response, sent a flurry of dozens of images to her brother's phone.

The resulting deluge was the most concentrated display of depravity Makoto had ever seen. Sailor Scouts in a futanari gangbang that violated several fundamental laws of biology. Bonnie giving Clemont the deepest rimjob he had ever witnessed, in art or on the internet. An image of a tall man and a short girl engaged in intercourse, that was a bit too blurry for Makoto to be comfortable with it.

All the while, Komaru smiled at him with that slick smile.

Makoto kept scrolling. There were words he would take years to recognize in that flood, like guro, or omorashi. It was sickening and yet, when he saw that smile from Komaru it was almost...cute?

Komaru stood outside the door as she heard the water running, her heart racing. She hadn't actually seen his thingy since they'd done the sex, and she was nervous about it. But even so, their parents weren't home again, and it was the perfect opportunity, so she stepped inside, and immediately saw Makoto's shadow through the shower curtain. She even could see the outline of his thingy, standing at full mast, making her heart race faster as she closed the door behind her.

Makoto exhaled as he gently dragged his hand along the length of his penis. It had been growing in size recently, one of the 'joys' of puberty, and his libido had been growing more and more recently. The shower was one of the few places he could easily relieve himself, preferably without intrusive thoughts of...her.

Silently, she faced towards the curtain, and started to strip down, slipping her shirt up and over her head, before reaching behind her back to undo her training bra.

Sudden movement made him jump, and nearly fall. A shadow, clearly visible against the curtain. One shaped like- "Komaru!"

Komaru stayed silent as she pulled off her bra, and then pulled down both her shorts and panties in one swift motion, before setting herself up on the counter, wincing at the cold marble against her butt, before she spread her legs, and began masturbating as she stared at the shadow of Makoto's thing.

Oh god...she was really doing it. Makoto froze in place as his cock started throbbing. Could he...could he really resist?

Komaru started to moan as she slid her fingers against her lower lips, which were slowly getting wet, as she slid her other hand up to her chest and squeezed her breast as best she could.

The sound of her moaning was what got to Makoto long before he realized what she was doing with her hands. "Komaru," he practically whispered. "Do you...want to come inside of the shower? With me?"

Komaru paused, and looked over at him, stunned. Had…had it finally worked? "A-are you being serious?"

"Yes...get in here, please."

Komaru wasted no time jumping up and walking over and slipping inside the shower. As soon as she saw Makoto, her breath escaped her. Immediately her eyes shot to his thing, which somehow seemed even bigger than before, and her body trembled. She had to hold herself back from immediately jumping him and slipping that thing inside her.

It was Makoto who acted first, stepping forward and kissing Komaru on the forehead. It wasn't what either of them expected, but frankly, Makoto had no idea what he was doing.

Despite herself and the situation, Komaru blushed, and she reached a hand out and gently stroked a single finger across the length of his thing. "H-hey Makoto?"

Makoto shivered under her touch. Her hand seemed so soft, all of her was just so inviting- "Yes?"

"Wh-what's this called?" She asked, gently poking and prodding his thing.

Makoto chuckled a little. All of that art she sent him, and yet- "It's called a penis, Komaru."

"Penissss…" She said softly as she pinched a finger on either side of the shaft and stroked it.

Makoto's hips jerked as Komaru worked him over. The unexpectedness was a large part of what made things feel pleasurable, and the other pleasurable part was how he was able to reach around and take two great handfuls of her pert ass.

"EEP!" Komaru jumped, and shuddered as her legs trembled. "Y-yes…" She said, wrapping her hand around his cock and squeezing it gently.

Makoto played with her for a bit before pushing her back a little. "Get on your knees," he ordered, whispering in her ear.

Komaru felt disappointed when he let go of her butt, but she did as she was told, and got on her knees, soon finding herself eye level with his penis.

Makoto gripped the base of his dick and tapped it against Komaru's cheeks a few times. "You browse enough...weird art, do you know what a blowjob is?"

"I…n-no…" She admitted, having only found all that stuff through looking up the character's names plus the words "sex" and "naked".

Makoto gave her a smile. "Here, it's easy, open your mouth."

Trusting him, she opened her mouth.

Makoto dropped the head of his penis onto her tongue. "Now, close it. Don't let your teeth touch it."

Komaru did her best to nod, and closed her mouth around the head, and pressed her tongue against the skin.

Makoto let out a loud, long moan. "Yeah, just like that. Try sucking on it now."

Komaru slowly moved her head back and forth, sliding her tongue against his penis, the taste very weird, but still doing as he said.

Makoto gripped her hair, tight, and guided her head along his shaft, carefully keeping from gagging her, and delighting in the build of pleasure she gave him.

Komaru wanted to ask if she was doing it right, but based on the expression on his face when she looked up at him, she was, so she kept going, slowly moving further down his penis, taking more and more inside her mouth.

Makoto pulled Komaru off of his dick and practically lifted her up by her hair, before pressing her against the shower wall and pressing his body against hers, his dick prodding at her pussy. "Are you ready?" He moaned in between kisses at her neck and shoulder.

"I've been ready for weeks…" She said, managing a smirk as her heart raced.

Makoto inhaled before thrusting inside of Komaru, maybe a bit too roughly, as his hands moved down to her hips, taking firm grip of them.

Komaru cried out in pain as it finally entered her for the first time since that other time, and while it felt very painful, it was still extremely pleasurable as well, everything she'd wanted it to be.

Weeks of pent up need manifested in the way that Makoto thrust into her, making her entire body shudder and her chest heave with every slap of his hips against hers. It was clear now that she had been right the whole time, she needed this, he needed this, they need each other.

"M-Makoto!" She cried out as she held him tightly. Every single thrust sent waves of pleasure throughout her entire body, which screamed for more and more.

"Komaru," he returned, more quiet, huskily. Pressure was rapidly building inside of him, and the only thing he could do to compensate was fuck her even harder, reaching up with one hand to grab a breast, squeezing it as tight as he could in some vein attempt to vent the pleasure flooding his body.

"I…I love you, Makoto!" She shouted, feeling that pressure she'd come to know so well these past few weeks building inside her.

Makoto was too overcome to talk, instead leaning forward and biting down on her collarbone as he fully hilted himself inside of his sweet, little sister; releasing a torrent of cum inside of her with a moan muffled by her skin.

At the same time, Komaru also moaned as she came too, her fluids mixing with his as they both finished together in the shower in a beautiful display of love and lust.

Makoto finally pulled out of his little sister and released his 'grip' on her, watching a bit of blood well up from the skin before being washed away by the shower. They looked in the eyes for a moment before he leaned forward to kiss her.

She kissed him back, feeling the water cascading down their bodies as she held him closely, hoping that, unlike before, this wouldn't be a mistake, an accident, but rather, an indication of what was to come.

Makoto reached under Komaru to lift her up, bridal style, and carry her out of the shower.

Komaru giggled against his lips as she was carried, dripping water onto the floor.

Makoto stumbled his way out of the bathroom and into his bedroom, not caring about the water they trailed across the carpet, or the stain Komaru made when he threw her on the bed.

"Makoto?" Komaru asked as she looked up at him with confusion on her face.

"We have a few weeks to...make up for, don't we~?" He practically purred as he jumped on the bed as well, pressing Komaru down with his own body.