The trouble began, not for the first time, with an apple.
They lay big, round and red on doctor Yagokoro's desk and, if they would have known the future they would have ticked like bombs.
The harvest season was coming to an end and Kaguya had been extatic to see the appletrees she planted from seeds roughly ten years ago where ready to bear their first fruits. Sadly, before the harvest could comence, a firery duel with her archnemesis had reduced the lovingly cared for plants to ash and Kaguya never had a chance to taste the fruit of her labors. Kaguya was inconsolable. Eirin proposed to visit the Aki sisters on Yokai Mountain to aks, if necessary force, Minoriko to part with some freshly grown Apples, or even easier, just send Udongein to buy some at the Human Villiage. But the princess sneered on those ideas. They needed to have grown here in Eientei soil. Apples that where as beautiful as her, touched by the eternity and purity of the moon, but still have their earthly roots. Not willing to put up with Kaguya's moping and whining Eirin proposed to help nature to speed up the process a little and grow some apple trees in record time. By some kind of magic Kaguya brightend up at the idea of having super trees in the garden and was happy to have Eirin have a go at it.
It took the better of the week to modify a regular seed into a super seed that would grow in an adult tree in days instead of years and another two sleepless nights to mix a serum that would trigger fertility in the soil necessary to grow such splendid plants without making them die by their own rapid growth. Poor Udongein was running ragged with all the errants for exotic materials and magic formulars. But on the second last day of Autum Erin had grown truly amazing trees. Eirin couldn't help but feel pride in her work, as she watched the apples gleam in the sunlight of the late autumn sun. But bevor Eirin let Kaguya harvest and eat those fruits, she wanted to conduct a few test on them, to make sure they where actualy safe to consume. Playing god with nature hat the unfortunate habit of sometimes exploding into your face with unexpected and unwated side effects. Like exploding for example. While Kaguya was indeed as imortal as any being could wish (or not wish) to be, Eirin had a trusty student/Guinea pig who could test them out. Of course Kaguya complained that she didn't get the first taste of her labor, but Eirin just retorted that it was her labor that grew those trees and she decided that Udongein had the honor to play taste tester.
"You wanted to see me, master?" asked a nervous Reisen. She didn't want to play Guinea pig for her masters newest shady sheme but what could a pet do?
"Have an apple, Udongein, and relax. I just have a few questions fo you," Eirin said and handed the rabbit youkai one of the apples. Reisen looked at her as if she had offered her a fistfull of spiders, sighed then and took the apple.
"What are you waiting for? Take a bite," Erin orderd. Reisen eyed the apple in her hand wearily. It looked harmless and innocent. Just a fruit. It had no sickly green or purple colour, nor did it glow in a concerning way. She closed her eyes and braved her first bite. Her mouth exploded with heavenly flavor. Juice ran down her chin and she greedly took another bite.
"My, my. That good?" asked Eirin and laughed. With a swift motion she stole back the apple from her student.
"Hey!" shouted Reisen angrily, "i was eating that."
"And i decided that you will stop now. You can have the rest later. So, how are you feeling?", asked Eirin and took a clipboard and a pen from her desk.
Reisen thought about it for a moment.
"I don't feel any different, than bevore the apple," she replied.
"Really?", asked Eirin and made a note. "And how did it taste?"
"Amazing!" gushed the rabbit youkai and bringing her hands to her chest. "That apple was the best thing i ever tasted. Do you remember the cake Tewi had made for the princesses birhtday? That! But times ten!" She started to feel warm. It spread from her stomach to her chest.
"What's wrong Udongein? You're looking kinda red? Are you feeling something now?" asked Eirin curiously.
"I feel warm in my stomach and my chest," Reisen said and started figeting. After a short while she added quietly "And in my... neithers..."
"Really?" Erin eyed her student.
"My chest feels... tight. It feels like with every heartbeat something flows into it," Reisen explained. She moaned. "It feels really good..."
Reisen started kneading her breasts earnestly her nipples getting erect and rubbing the inside of her bra. It was almost as pleasuring as rubbing her already moisteingn pussy. Heat seemed to spread in her entire body but centralizing in her for attention aching breasts.
"Udongein?" asked Eirein concerned. The show her student was putting on was making her feel uncomfortable.
Reisen only moaned in answer as she fondeled herself furiously. Her chest felt tight, like something was growing in it, stretching it...
"Udongein!" Eirin called out alarmed. Reisen Chest was bulging bigger under her clothes, strainign the shirt and making her bra dig into the soft titflesh.
With an ecstatic scream Reisen ripped of the restraining clothes and let her growing boobs free. Her milky white breasts bounced and jiggled freely. Reisen's nipples where engorged and blistering red, screaming for attention and Reisen obliged them happily, twisting and stroking them. She mewled and moaned as her breasts became fatter and fatter only allowing her to stand because of her youkai strengh. Wettness traveld down her legs as her soaked panties couldn't dam the flood that had become of her pussy. Her Nipples had reached an obsene size and where now bigger than her thumb sending explosions of pleasure down her spine as she stroked and pumped her growing tits. White liquid began to leak out of her overszied teats lubricating her breastflesh and giving her ministrations a wet slapping sound. Finally Reisen found release and with one final scream of extasy she climaxed. Milk exploded out of her chest and made her eyes roll back. She collapsed on her her knees. Her Breast, which seemed to finally stop growing filled her lap completly, still leaking milk onto the wooden floor. Reisen panted heavily still shaking from her bombastic orgasm.
Eirin, who had watched everything wide eyed stared at Udogein slack jawed. What the fuck had she created? Where the effects permanent? Udongein had taken only two bites of the Apple. What would happen if someone consumed a whole fruit? She stared at the apple in her hand. It smelled sweet and inviting, daring her to take a bite.
Eirin congratulated herself for her quick thinking of not letting the princess have one. Who knows what would have happend? She had to be quick before some fool could think about eating an apple without wating for her okay. She made to leave her study and rushing to the garden.