Inside her house, Ai-chan poured with a starving look a good portion of ramen inside her bowl. Without even a slight hesitation she immediately attacked her diner, putting the noodles inside her mouth before slurping them down her throat. She swallowed them down and sighed happily. She licked her pretty lips before putting the bowl to her mouth and swallowed the rest of the soup. She sighed again as she felt her stomach full again and already working to give the energy she needed to maintain her amazing body. She gently rubbed her belly before turning her head behind her :

- Mom, can I...

- CAN I HAVE SECONDS ? screamed her little sister.

- How many pieces of mochi do you want ? asked their mother from the kitchen.

- Two, three...said the little sister, rubbing her belly in anticipation. No, four !

Their mother chuckled while Ai-chan gave her a dismayed look.

- You're eating too much, she scolded her.

Her little sister looked at her with a defiant look.

- I'm still growing ! And no matter how much I eat, I don't gain any weight ! she said smugly while presenting her profile to her older sister.

She showed her sizable breasts that were deforming her sweater quite a lot. For sure, she was clearly very well-endowed considering that she was only 14. Ai-chan slowly chuckled at her confidence.

- If you're not careful...

The older sister straightened her back, lifting her two enormous breasts up before letting them drop on the table with full force. Her two oversized mountains produced a loud thud as they crashed on the table, making the utensils and glasses shake and clatter. One could easily see just how tremendously heavy her bosom was as the shockwave affected the whole table. Ai-chan's stiff shoulders greatly thanked their owner for relieving them from such a hefty burden. It was clear that her bosom had reached such an important mass that it had to be now counted in kilograms.

- ...you're gonna end up like me, Imouto-chan, warned Ai-chan.

The younger sister looked down at her older sister's massive breasts. Each one was already bigger than Ai-chan's head. Her two gigantic mountains of flesh greatly surpassed every object on the table by a lot making it even more impressive. Ai-chan knew her warning was pointless as her young sister had already grown an imposing chest as well, albeit not as massive as her of course. In a way, she was talking to herself as Ai-chan too had quite an impressive appetite as well. Already, she could feel her stomach working to break down the fat and energy of her ramen. Her body would then hasten to bring an abnormal percentage of nutrients to her gigantic breasts, first to maintain their colossal sizes and secondly to make them grow even more. As Ai-chan was thinking about her body's mechanism, her stomach quietly growled and her bra squeaked softly, just as if it was telling her how right she was. Imouto-chan wolf-whistled at the sight of her older sister's impressive bosom.

- You've gotten quite huge, sis', giggled Imouto-chan with a mocking tone. However, unlike you, I plan on growing upwards, you see ! she added pointing her finger up from her head.

Ai-chan sighed with a smile. Hearing her young sister's delusion was quite comical.

- Good luck with that, how tall are you, right now ?

- Huh, 142 cm, no 143 ! she replied, her smile vanishing a bit.

- And what about those ? asked Ai-chan while pointing a finger to her sister's large breasts.

- F-cup...

Imouto-chan's smile disappeared as she understood the point her big sister was making.

- And your bra is a bit tight, right ? continued Ai-chan, raising an amused eyebrow.

- Y-yeah..., replied her young sister with a dismayed and worried expression.

Ai-chan chuckled with a big grin on her face.

- Well, well, well. Looks like you're roughly on the same pace as I was back in my second year in middle school...

Imouto-chan gasped and looked again at her sister's giant bosom. She was perfectly fine with her F-cup breasts, there wasn't any need to grow even larger, especially at this size. She covered her breasts to somehow make them smaller and whined :

- Eeeeh ! No way ! I don't want to look like a salmon fry when I'm in high-school !

Ai-chan sighed angrily before hitting the top of her sister's head with her fist, giving her a well-deserved bump. She continued :

- It's fine... at least you won't have to pay for anything.

- Uh ?

Ai-chan stood up and walked away to her room from where her young sister could hear rumbling through her drawer. She came back a few moments later before sitting down at the table again.

- Look !

She presented her a cute red bra with stars and frills embroidered following the curvature of the cups. It was indeed a quite beautiful bra. But as Ai-chan was showing it to her sister, it was clear that it was way too small for her to fit her enormous breasts inside it.

- Here, this is the bra from when I was a second year. Looks cute, doesn't it ?

- I don't want hand-me-downs ! Buy me some new clothes for once ! Who wears hand-me-down bras anyway ? squealed Imouto-chan.

- It'll look good on you, replied her big sister, forcefully putting her bra on her sister's hand.

Once again, she lifted her huge breasts up before letting them rest on the table.

- Besides, I only wore it a few times. It'd be a waste to throw it away.

Imouto-chan reluctantly looked at the bra in her hands. It was a G-cup bra and even a rather large one. It was a little too big for her at the moment but she must have to face it : there will be a moment where it will finally be at her size. It was a rather odd thought to compare it with the massive size her big sister was now displaying. Somehow, she made it look so small. Imouto-chan then thought about something : it was not any G-cup bra... it was... her sister's bra. And her sister was rather incredibly popular, wasn't she ?

- This bra, started Imouto-chan with a grin, it has the sweat of your cleavage seeped into it...

Ai-chan frowned and looked at her young sister with a worried and disgusted look. Imouto-chan looked at her with a wide grin :

- I'll fetch such a good price from the boys of your high school...

- What !?

Imouto-chan quickly pulled out her phone and tried to take a picture of her big sister with the G-cup bra laying on the table as evidence. Ai-chan squealed and covered her massive bosom while turning away to hide her two assets.

- Stop it ! There's no way you're going to sell one of my bras to them !

- Come on, sis' ! Move your hand ! We can share the profit !

After having smacked again with her fist her young sister's head, Ai-chan put her bra back in her bedroom's drawer and came back. Imouto-chan was laying on the table, scratching the top of her head where a second bump had now appeared.

- I don't want to become like you, big sis' ! I'm going on a diet…, she said sadly.

The two teenagers heard a chuckle from behind them. It was their mother who left the kitchen with a tray and all the food she had been cooking since the beginning. She was a rather wonderful and beautiful woman in her late 30's. Her hair was way longer than her daughters and she shared the same light green color of their eyes. But that wasn't the only feat she had in common with them as one could easily see her apron bending from her two huge breasts as well. She sat in front of them and started to display the food on the table.

- Everything we eat goes straight to our breasts, she said. That's the fate of our family, she chuckled.

Ai-chan tilted her head with a mocking grin to her young sister.

- You heard her, give up.

As Ai-chan started to eat her second plate, her young sister was not having it.

- Mom, can I ask you something ?

- Yes, dear ?

- How big are yours ?

- Oh my ! I think I'm around an H-cup.

A glimmer of hope sparkled in Imouto-chan's eyes. Ai-chan looked at her from the side as she was eating her ramen. She smiled mentally as she knew what she was thinking.

- Yeah but big sis' is a J-cup ! joyfully said Imouto-chan. If you're a H-cup, that means there's a good chance for me to not grow as big as her !

Ai-chan chuckled and Imouto-chan looked at her. Without even stopping to swallow her soup, Ai-chan made a "no" gesture with her index and gave her an amused side-look.

- Well, you're both quite incredible, I must say, replied their mother with an amazed and proud smile to her daughters, but I wasn't anywhere near a F-cup at your age, my love. I think I was around a D-cup.

Ai-chan and her mother could easily see Imouto-chan's hope shattered in her eyes as she understood she was rather going to follow her big sister's path than her mother's. Ai-chan sighed as she finished eating her second bowl.

- Give up, repeated Ai-chan with a mocking tone.

- Nooo, whined her young sister, rolling on the floor. I'm already fed up with the glances of my middle school's apes !

- You should get used to it…, sighed her mother

- It's worse in high school, replied Ai-chan as her phone rang. Oh, sis' ! The friend I talked to asked if you want to go to the shrine for new year's eve.

- Senpai ? Yes, sure !

As Ai-chan replied on her phone, she noticed that her young sister wasn't eating her second bowl of mochi.

- You're not eating now ?

- I'm on a diet ! angrily replied Imouto-chan.

- Well, you can try...

Ai-chan took her sister's bowl and brought it towards her. As she picked up a piece of mochi with her chopsticks, her sister asked, incredulously :

- You're still eating ?

- I gave up on my fate, winked Ai-chan

The Ebisu shrine was the biggest in their town and there were always a lot of people for New Year's Eve. Ai-chan and Imouto-chan were walking in the crowd when they heard a familiar voice :

- Hey ! Happy new year ! joyfully said Volleybu-chan.

- Happy new year, replied Ai-chan

- Eeeeh ! A happy new year to you too, senpai ! happily screamed Imouto-chan.

Volleybu-chan and her hugged each other strongly. They knew each other only for a couple of months but they managed to form a very strong bond together besides the fact that they were in two different schools because of their age difference. Ai-chan approached Volleybu-chan and took her jogging's zipper.

- You should zip up ! You'll catch a cold, you tomboy !

- Eeh, you act like you're my girlfriend, giggled Volleybu-chan.

- Let's get going ! said Imouto-chan, wrapping her arms around Volleybu-chan's right one.

As they were walking inside the shrine, Volleybu-chan couldn't help but marvel at the two young girls. Of course, her best friend was by far the most beautiful girl here but her young sister managed to get some incredible features as well making her quite stunning too. Especially of course, in the chest department. If Ai-chan's peacoat was so incredibly curved, Imouto-chan's one showed that she was also having quite a lot of assets herself.

- Hey look, it's Miko, said Ai-chan.

In the distance, they saw an acquaintance from their high school. She was a young girl with quite long straight hair. She was wearing a long shintoist uniform with long sleeves and lots of underlays tightly wrapped around her thanks to her very slim figure.

- Her uniform looks so nice, I should get a job here.

Both Imouto-chan and Volleybu-chan looked at her with amusement.

- I don't think you'll fit in, girl ! joked Volleybu-chan.

- We can't tell, replied Ai-chan in denial.

Of course she couldn't and she knew it. Miko was nothing more than a B-cup at the very best.

- Let's go to the food stalls ! hungrily said her young sister.

- Sure, replied their friend.

- I want this, and that, and... that, and...

- Weren't you on a diet ? mockingly asked Ai-chan

Imouto-chan stopped and showed a rather sad face. She obviously forgot about it. She was so desperately hungry now and didn't expect it to be so hard to follow a diet. She squeezed her breasts a bit, trying to see if she had at least lost a bit during her day of fasting.

- Senpai, what do you think of big boobs ? she asked.

- Big boobs ?

Volleybu-chan stopped to think about it. Ai-chan stopped as well and lowered her eyelids in amused annoyment. It was clear that her friend was recalling every jiggle, every bounce, every crease on her shirt and every fondle she gave to her. Ai-chan actually wondered for an instant who was more in love with her enormous breasts between her and Onii-san.

- I think the bigger they are, the better, plainly said Volleybu-chan.

Ai-chan sighed but couldn't help to feel a bit proud even though she obviously couldn't show it. Her young sister looked at her big sister's huge bosom.

- The bigger they are, the better... she slowly repeated. Alright, I want five skewers of chicken, three of beef, three of... ! she yelled to the vendors.

- Look what dangerous mindset you put in her head, said Ai-chan to Volleybu-chan who chuckled in response.

Her young sister came back with around 15 different skewers, grabbed two and put them in her mouth.

- Wait for me, senpai ! I'll surpass big sis' in no time !

Volleybu-chan laughed at her statement while Ai-chan sighed a bit. Was her young sister really stuffing herself just to beat her in a chest competition ? She was 4 cups ahead of her but she'll let her have it if she really wanted to. If only she could trade for a normal-sized body.

As they walked around the shrine, Ai-chan put her hands in her peacoat's pocket and found a little object. She pulled it out and saw it was a small button she had popped from her school uniform three days ago. She had carefully placed it in her peacoat for next Monday. Thinking about it now, she remembered all the time Onii-san awkwardly looked at her oversized bosom, his physical reactions when she was leaning on him both on his face but also... lower. She couldn't deny it, she loved it. She loved it so much. As well as with her school's boys too. Sure, they were quite a pain most of the time but considering how many people have confessed to her in a matter of months, she couldn't help but be a little proud. Turning the button in between her fingers, she recalled more and more memories with Onii-san, how easy it was to tease him. She already beat her mother and every other girl she knew in terms of breast size and beauty, even Kouhai-chan from the mode industry. Could she let her young sister take the lead ? No way. She discreetly stole a beef skewer from her sister who was still talking with Volleybu-chan. Actually, there wasn't any reason to be afraid, she thought while taking a bite. As a matter of fact, Imouto-chan was quite behind her in terms of size. At her age, she was already a G-cup going to a H-cup before the end of the year. She swallowed the last piece with a sigh and immediately felt her stomach rumbling, starting her digestion. After all, she was still growing and this J-cup bra kept being fuller and fuller as days went by. She put back the button in her pocket and chuckled a bit.

"There will be plenty of buttons to come to you, Onii-san", she thought.