You Watanabe and Kanan Matsuura were enjoying a casual swim in the ocean around their beachside hometown.

"This is great, Kanan~ None of the other girls can keep up with me as well as you!" You cheerily said to her senpai.

"I'm certainly surprised, I'd figure you'd be so used to swimming in a pool that you wouldn't be able to handle the ocean's ebb and flow."

"Nah, being a competitive swimmer, I've trained in the ocean a lot to make swimming in pools even more of a breeze!" with that statement of confidence, You did her signature "Yousoro!" pose and gave a toothy grin, showing off her perfect smile.

"I love scuba diving, but it is nice just to wear my casual swimsuit for once as well," said Kanan, looking down and admiring how good her blue striped bikini looked on her.

You was sporting her usual skintight competition school swimsuit. It clung to her body and showed off her amazing curves. It was quite the feat that both girls could have such sporty bodies honed by the water, and yet exude very different appeals. Both had figures to die for.

As the sky filled with beautiful shades of red and orange, the girls swam back to shore and walked to Kanan's house nearby.

--

"I'll hop in the bath first, it'll be quick," Kanan said, leaving You alone in her bedroom. You stripped out of her still moist swimsuit and grabbed a fluffy white towel from a pile.

"You'd think being covered in water would prevent your body from sweating as much, but I somehow manage to sweat up a storm every time..." You thought. She took the clean towel and began wiping down her body, starting with her armpits and breasts, eventually working her way to her thick inner thighs, ass, and feet.

"I'm out of the bath! Just gonna grab something to drink from the fridge, you're welcome to jump in!" You heard Kanan's voice from the kitchen downstairs.

"Thanks! I'll be quick as well, just need to let my muscles soak for a bit." You called down the wooden staircase, heading into the bathroom.

Upon entering, You saw a pile of dirty clothes in a hamper presumably belonging to Kanan. She had to admit, her senpai had great taste in underwear. However, something was... alluring about the clothes pile. There was a very discernable scent wafting from the various pieces of clothing that tickled You's nose in a good way. She had never had these kinds of thoughts about a girl other than Chika before, but her curiosity was getting the better of her.

Making sure the coast was clear, You took Kanan's still wet bikini that she had just been wearing and held it in her hands. She had thought that their breast sizes were relatively similar all this time but looking at the bikini top and putting it to her chest, she could easily see Kanan's breasts were slightly larger. The bikini bottoms however showed a clear difference, Kanan's thighs and ass were a good deal larger than You's.

Clenching her first and letting out a sigh of defeat, You was ready to put down the swimsuit and take her bath, but thoughts of Kanan's naked body ran through her mind, and You's privates began to stir. Deciding it was now or never, You quickly took her friend's bikini and pressed it to her nose, inhaling a scented mix of the ocean, Kanan's sweat, and her natural body odor. It smelled wonderful, You thought.

Deciding she needed more, You kissed and licked the used dirty bikini top. She imagined Kanan's large breasts being cradled in these cups. One hand held the clothing while the other was down at You's crotch.

Suddenly a strange tingling feeling overcame You, but it was different than the tingling feeling coming from masturbation. It felt like an electricity was flowing through her, and she began to get dizzy. Putting the swimsuit back into the dirty hamper, You stood silent in the bathroom for a moment. The space around her blurred as the walls grew further away, and You's line of sight became shorter. She groggily walked to the bathroom mirror to see she had clearly shrunk in height!

Originally standing at around 5'1 (157 cm), You estimated she was now no more than 4'7 (140 cm)! Panic set in as You weighed her options. Surely her reliable senpai would know what to do.

Leaving the bathroom still stark naked, You briskly walked back to Kanan's room across the hall. But when she opened the door, what she saw shocked her.

Kanan was fervently sniffing the towel that You had used to wipe her body's sweat with. All while touching herself as well, just as You had done.

You tried to rationalize so much happening at once, all she could get out was "K-Kanan... I--"

"Stop! This... isn't what it looks like... I was just... reusing your towel since I didn't want to dirty another one and.... woah..." Kanan tried to explain as she began to feel dizzy. Putting her hand to her forehead, she sat on her bed dazed and confused, feeling as if the room was enlarging before her eyes.

You watched on in a stunned fascination as Kanan began to shrink before her eyes. From 5'3 (162 cm) to a mere 4'3 (130 cm), an even more drastic reduction in height than she had experienced moments before.

"W-what just happened to me!? You, what's going on!?" Kanan said, deeply embarrassed and confused.

"I... I think we have a lot to talk about, senpai..." You replied calmly.

--

Half an hour later, the two girls sat on Kanan's bed. You had gone back to take her bath, and now they sat huddled up next to each other drinking some hot tea in their pajamas. Their heights had only been restored slightly over the past 30 minutes, each gaining an inch or two at most.

"So, you're saying the reason we shrunk was because... we were affected by each other's sweat?" Kanan said, almost laughing from the absurdity of the situation.

"Yes, err well no... I'm not entirely sure yet. I have a feeling it's not just our sweat. It could be "anything" coming from our bodies potentially," replied You.

"Eww.... that's... kinda gross, in a hot way," Kanan both laughed and cringed at the thought. "I wonder if there's a way we could grow things as well as shrink them."

"...Do you want to try? I'm up for experimenting..." You began to blush before she could finish her thought and turned away to hide her reddened face.

The two girls shared an intimate day together that culminated in an intensely intimate evening. Figuring out how they should proceed with so much new information about each other, they decided it might be best to keep running with this weird development for now...

--

"W-well... if you're up for it... I am too... We should take things slow though. Who knows how dangerous these abilities could be" Kanan responsibly answered.

"Of course! I won't deny how anxious I am to see how far we can take these weird effects though..." You muttered.

Kanan let out a sheepish laugh, still a bit nervous but cautiously curious about the situation. "Alright, where should we start?"

Despite being the younger of the two, You had much more mischievous thoughts brewing.

"I have a few ideas...~"

The platinum-haired tomboy had a wild smirk that Kanan saw right through. She knew there was a thought or two brewing in her underclassman's mind.

"You, what are up to--mmpf!" Kanan was cut off by You casually tossing her previously worn clothes right in her face.

Nearly pouncing on top of her, You pushed Kanan down onto her own bed and used her hand to force the smelly pile of clothing onto the third year's face further. Kanan couldn't breathe as You's sweat-stained tank-top and socks were shoved into her mouth. She was forced to breathe in the heavy odor emanating from the soft soiled fabric. You's natural musk after a long day of exercising in the hot sun was intense, and Kanan knew this from smelling her clothes earlier.

You expected Kanan to fight back even a little bit, but apart from a few struggles for a second, Kanan seemed to settle down on the bed. You could hear Kanan's heavy sniffs of her dirty clothes, and it turned her on knowing what was about to happen. She imagined Kanan getting small enough to hold in her hands. She wasn't sure how far this shrinking stuff could go, but wanted to go all the way with it.

Still holding her pile of smelly clothes to Kanan's face, You began to softly touch herself down below. She stared at her senpai's large, heaving breasts, moving up and down with every whiff. Kanan was also getting turned on again, her quiet moans being stifled by the dirty black socks covering her mouth. She got a full taste of You's salty sweat and delightfully foul foot odor.

You's smirk grew into a devilish grin as she motioned her hand to move her worn blue panties near Kanan's nose.

"Mmmpf!" Kanan let out another moan, this one actually heard by You.

Both school idols blushed, not sure how far they actually wanted to go. Kanan was visibly starting to shrink, and You released her hand from Kanan's face to watch the action.

You laid her head on Kanan's toned tummy and felt a warm energy radiating underneath her cute pajamas. Kanan still smelled clean from her recent shower. She looked over to the blue-haired girl's face and still saw her smelling away at the clothes You was just wearing earlier. You could feel Kanan's body slowly shrinking away underneath her. The tummy she was using as a pillow was getting smaller and smaller.

Kanan went from 162cm to 160... 158... 155... 150... 145... 139... The shrinking was rapidly getting fast. Soon Kanan was the size of a small child. You giggled at the thought that even Ruby would tower over her now.

Despite seemingly taking this in stride, Kanan was now getting a bit scared, her field of vision was being covered up by You's dirty clothes, and all she could smell and taste was her friend. She wondered just what her fellow school idol had planned for her. She trusted You, but obviously there was a fear in getting so small.

Kanan was small enough now that You's socks couldn't fit in her mouth anymore. The pile of clothes created a complete blanket of Kanan's face that shut her out from the outside world. She was approaching 100cm now, barely the size of a 4-year-old. You smiled with glee, she couldn't believe this was actually happening. Knowing Kanan couldn't escape at this point, You moved her hands cautiously towards Kanan's still large chest. Despite being the height of a child, she still had the body of a young woman, and You was enraptured by the mature girl's breasts.

You's breasts were also impressive, but her senpai's were a sight to behold. Her hesitant fingers snuck their way to Kanan's perky nipples. Obviously she was turned on by this situation as well. It made You feel less guilty for what she was about to do.

She pinched the nipples of her shrunken friend just as she was the nearing 90cm mark. Kanan was understandably very shocked by this and cried out in a pleasured moan.

"Y-You... stop..." her higher pitched voice could be heard muttering from underneath the clothes pile.

"O-oh, sorry..." You replied, now feeling she went too far.

"Nngh... n-no... it's okay... How small am I...?"

"You're like a toddler now. I can't believe how cute you are, senpai. I can't wait for you to be even smaller..." the larger girl confessed.

"God... hearing you say that is kind of hot... What would Chika and the others think if they saw us...?"

"C-Chika?" You gasped. She hadn't even thought about her friends this whole time. But it was a fair question. You had feelings for Chika, and everyone in Aqours knew this. You realized she had to set aside her feelings for now and focus on what was happening in front of her.

"They'd probably think we were crazy... I don't think these feelings are something everyone would understand... It's the same for you and Mari, right?" asked You.

"Eh!? Y-you knew!?" Kanan shot up, the clothes falling off her face and landing in her lap.

"We all knew. But maybe there's some things in our group that are better left unsaid... don't you think?" You's mind went back to Chika.

"You..." Kanan looked at her friend's longing expression.

The pair realized they might have soured the mood talking about their unrequited loves. They both stayed silent for a moment, unsure of what to say. Neither wanted to admit that they were potentially using this situation to cope with the fact they might never be able to get intimate with the girls they respectively had feelings for.

--

You glanced back down at Kanan's nude body, still steadily shrinking away into her pajamas. Kanan was covering her (relatively) large breasts with her arms. Her legs were also crossed to hide her crotch, and You found this sight so amusing.

*giggle* "Senpai, your body and voice are so cute and small now. Look at yourself," You said as she grabbed a mirror off the bedside table and showed the still shrinking girl.

"I-is that really me...? Gosh.... and You, you look huge....!" Kanan gasped, now just realizing she was having to crane her neck upwards to meet You's eyes..

Kanan had nearly reached doll size. Her pajamas were now a baggy pile of cloth surrounding her, and You got a good look at her friend's nearly naked body.

"Kanan-senpai, you're... still shrinking..."

"Eh? Ah... y-yeah I am... maybe we went a bit overboard. I did have your nasty clothes in my face for a while," Kanan nervously laughed.

"Hey, I could tell you were enjoying it! I think we both were," You replied, still feeling her privates stir down below. She remembered the feeling of Kanan's nipples between her fingers and she blushed.

Kanan could see this obvious tell and laughed again. "You're thinking something perverted again, aren't you?"

"N-no! I just... Well... okay yeah, maybe... I've just never really done this kind of thing with anyone before, let alone a girl..." You looked down at her feet in embarrassment.

"There's nothing to be ashamed of, You. After all, I don't think anyone's done this exact thing before. I mean look at me! If it's about us both being girls, well... who are we to deny those feelings about ourselves?" Kanan openly pondered.

You looked back at her senpai, now smaller than doll size. She was shrinking away into her own pajamas while You's dirty socks and panties laid in front of her. Both girls smiled and You knelled down in front of the bed to get a good look at her beautiful tiny friend. Kanan stared up into You's gorgeous blue eyes. They sparkled in the evening glow of the moon.

Both girls' minds were occupied with many thoughts. About their unrequited loves, this strangely erotic situation they found themselves in, and how far exactly they were willing to go tonight...

--

You grabbed her phone and looked at the time, realizing she hadn't checked for a while. She was greeted with messages from Chika, sending her memes she knew her friend would enjoy. You smiled a soft and slightly melancholic smile, knowing she'd never win over Chika's pure heart if she pursued someone else out of desperation. You decided it'd be best if they called it quits for tonight.

"What's the matter?" asked Kanan, wondering what her large kouhai was staring at.

For a moment You got flustered and almost dropped her phone on the tiny girl, "Ahhh um it's nothing! Wow, look how late it is! We really should get some sleep, we still have morning classes tomorrow!"

"But you were the one who wanted to try out these weird powers... you aren't in the mood?" Kanan was a bit disappointed to hear that You wanted to stop, but she was slightly relieved as well. Truth be told, she was missing Mari's company quite a bit.

"Y-yeah... You're right... but we don't have to stop completely tonight... I actually have one more idea..." You's mischievous grin from before had disappeared, her voice and smile were much more sincere. From that, Kanan knew she had Chika on her mind again.

"Sure, what did you have in mind?"

"What if I kept you small while we slept tonight, pretty please?" You gave her best pleading expression.

"How would we do that? No offense but I'd rather not sleep in your dirty socks, as slightly appealing as that sounds." Kanan giggled. At this point their bodies and minds had cooled off, and the inherent eroticism of shrinking had slightly faded.

"No not exactly that, but maybe something similar. What if I held you close to me, like a doll? We could... cuddle... m-maybe..." the platinum-haired idol blushed deeply.

From all her bravado before, now she was getting embarrassed over cuddling? Kanan found this adorable, and couldn't help but let out a laugh.

"Sure! That honestly sounds kinda fun. But umm, please try not to crush me in your sleep. I might not even be doll sized by the morning."

"I-I won't! Though... it is a hot night... I can't deny I sweat a lot in my sleep..."

"Fufu, such an innocent request from the girl who was just throwing her panties at me earlier. What happened, really? You can tell me."

You felt comforted at her senpai's maturity, even in a situation like this. "I just keep thinking about her, I can't help it... The thought of shrinking her like I did with you even crossed my mind... I'm sorry if I was too forceful with you earlier. The power kind of went to my head..."

Kanan stood up, still covering her privates now that she had no clothes protecting her, and walked across the bed to her giant underclassman. She placed her tiny hand on You's knee and looked into her bright blue eyes.

"It's okay. It's not like I didn't want to try this stuff out either. Chika and you will be just fine, I know it." With those kind words of encouragement, Kanan gave You a pat on the knee and walked back over to her pile of clothes.

"I-if I promise to open up to Mari, will that make you feel better? I feel as if I have an obligation as your senior..." You looked down at Kanan, not even attempting to hide her nude body now, fully intent on making her feel better. It relaxed her and allowed You to regain her usual spirit.

"It's a deal!" You gave a blindingly bright smile.

Kanan gave the girl's knee one last pat and turned around to walk back to her pile of clothes. Her cute naked butt swaying caused You's blood to rush back to her cheeks, she was all perked up and ready for fun again.

"Kyaaa! I can't with you anymore! You're too cute!" You girlishly gasped as she reached down and plucked her senpai's naked body off the bed. She felt the girl's mature body squirm between her fingers, her skin was so soft.

"Y-You! What are you doing!?" Kanan said exacerbated. "Y-you're being way too touchy!"

"I can't help it! Just look at you! Anybody would kill to have a body like yours to themselves!" as she said this, You poked and prodded the school idol's shrunken form, fully fondling her breasts and ass.

"O-okay that's enough! We should seriously get to bed, it's been a long night, and I'm tired..." Kanan shouted, feeling herself getting wet down below from You's fondling. She didn't want the younger idol to find out she was that easy.

"You're right, let's get some sleep my little pet~" You giggled, setting Kanan back on the bed. You got up and stretched before taking the pile of clothes and putting them off to the side. She climbed in Kanan's bed and let out a yawn.

"I just realized, it's kinda weird I'm sleeping in your bed, senpai."

"I guess it is. It's weird, I'm almost getting used to being the size of a toy."

"Maybe by the morning you'll be the size of a bug if I keep you close to me," teased You.

"L-let's hope we don't find out... By the way, where did you want me to sleep exactly?" asked the blue-haired beauty.

"Right here," with that, You unbuttoned the top to her pajamas, exposing a generous amount of cleavage. Kanan most likely had the best body of Aqours, but You's similar curvy athletic build was no slouch either.

"Oh my, how scandalous~" joked Kanan. "What would the media do if they found two school idols sleeping together!" she let out a fake gasp and walked over to You's awaiting palm.

The tiny girl stepped onto You's soft skin and she was lifted up close to her kouhai's body. You used two fingers on her opposite hand to part her breasts and open up some room for her senpai. Kanan was nearing 15 cm (about 6 inches), which made it easy for You to slot her naked body right between her soft breasts. Kanan's squirming tickled You a bit, but she soon got used to the feeling.

You laid down and pulled the covers over her. Since she slept on her side, Kanan was laying down on one breast while the other covered her like a blanket, or rather a giant pillow.

"Good night, senpai," said You softly. Her eyes slowly closed as she drifted off to sleep with ease.

"Good night, You," replied Kanan.

You's prediction was indeed correct, she could already feel the sweat on the giant girl's breasts accumulating. And while it wasn't necessarily hot between the massive mammaries, it did make Kanan wish You at least put the AC on. It took a few minutes of moving for Kanan to get comfortable, but she finally did, and eventually fell asleep nestled in her underclassman's bosom.

Kanan wondered how small she would end up being in the morning.

Both girls dreamed of confessing their feelings to their respective loves.

--

The early morning sun shone through the thin curtains of Kanan's room. You rubbed her eyes as the sun's rays woke her up.

"Yawn... Right... I fell asleep in Kanan's bed last night..." the sporty girl mumbled. Having gone to sleep late in the evening, the girls hadn't had much rest. She pulled the bed's covers off her and sat up. Her bare feet landed on the cool hardwood floors which sent chills up the girl's spine.

"Brr... Oh, hey, Kanan!" You called out. She had nearly forgotten what transpired last night! "Kanan? Where are you?"

You looked all around the bed, and on her body, but there wasn't any apparent sign of the previously shrunken girl.

"C'mon senpai, where'd you go?" You worriedly asked. Surely she couldn't have shrank further in her sleep... right? A bead of sweat ran down her face upon that potential realization.

"Shit shit shit! Kanan! Please give me a sign, jump up and down and scream! I can't find you! I need to know if you're around!"

Still, there was no response.

You rationalized that surely Kanan, being the responsible one she is, would have gone to a safer spot than her cleavage if she knew she was shrinking. The platinum-haired idol calmed herself down, and hoped she'd see Kanan at school that day like always.

"Everything's going to be okay... Kanan woke up early and went to school... it's gonna be fine..."

--

Meanwhile, Kanan had slept like a rock. She quickly passed out in the massive and comfy warm cleavage of her kouhai. Upon feeling the tremors caused by You waking up, Kanan also awoke, rubbing the sleep out of her eyes. Preparing for a new day, she looked at her surroundings and saw... Nothing.

Or rather, she saw nothing but the vast, endless expanse of You Watanabe's breasts.

Kanan's blood went cold. It was like she was in another universe, an alternate Earth which was nothing but a desert made of soft skin. She was so small that the slightest of slight pores on the girl's skin were large hills to Kanan. She was so small that You's breasts became planets with their own gravitational pull. She looked up to see You's other breast hanging over her like a moon. The breast she stood on was an undiscovered planet all unto its own.

She needed help, fast. This shrinking experiment went further than it ever should have, and Kanan was now scared for her life. Looking at her naked body, it was covered in a thin layer of sweat. If she had to guess, it was all You's boob sweat. Laying in it all night caused her to shrink indefinitely. Even now she could feel the tingles caused by shrinking.

Quickly wiping all the sweat off her body she could, she quickly began running. Where to, she wasn't sure, her sense of direction was entirely off. Far off in the distance, the two planetoids met, making a deep, vast canyon of flesh. It was You's cleavage. What she slept in last night. Kanan thanked whatever little luck she had that she didn't wake up between those breasts, she'd have been entirely obliterated by them.

Kanan continued to jog, something she was thankful she was great at. Pools of sweat were all over the titty desert. The blue-haired idol dodged them with ease. Up above, it was clear You was waking up. Each minuscule movement caused massive tremors and shockwaves to Kanan's 'ground'. These earthquakes were larger than any magnitude she had ever experienced before.

"Yawn... Right... I fell asleep in Kanan's bed last night..."

The micro sized girl covered her ears. Damn her voice was loud! It was like the all-consuming voice of the heavens was being sent down from above. You continued to talk to herself, and though her voice was distorted to a terrifying degree, Kanan could somehow make out what she was talking about.

"You! You! I'm here! I'm down here!!" Kanan jumped up and shouted just like she was told. But it was no use. You's face was a blurry sky in the distance, there's no way she'd notice a girl smaller than her pores.

"Everything's going to be okay... Kanan woke up early and went to school... it's gonna be fine..."

"Damn it! She thinks I'm not even around her! This is terrible! I'm gonna die here!" Kanan wailed, tears welling up in her eyes. Kanan looked around for something, anything to help her in the vast plains of breast fat.

"Unless... No... but, there's no other way..." Kanan thought.

Surely if she made it to You's nipple, she'd have to feel her? She couldn't risk waiting for the shrinking to wear off, she didn't know how long it would take. And if You took a shower or her breasts even slightly moved an unfortunate way, she could be washed off or crushed easily! It was decided, the nipple was the most sensitive spot available, if Kanan made it there and made a racket, surely You would notice!

This plan was insane, but it had to work. Kanan couldn't waste any time, she altered her direction and began running towards the base of You's mountainous breast.


Destination: The areola of You Watanabe's massive left tit.