"I'll see you soon…"
Indistinct voices murmured at the edge of Sakura's hearing as she drifted in and out of consciousness, spots of darkness and light shifting in turn above her. She was vaguely aware that she was lying on her back due to the oppressive weight of her chest pressing down on her, but she couldn't summon the strength for any thoughts beyond blurred impressions.
"My son, Muku…"
Sakura groaned in discomfort as she instinctively sought to turn on her side to breathe, but her wrists and ankles were bound, holding her fast in place. Her eyelids fluttered as she fought to stay awake, aware of some immediate danger, but she was sinking deeper into unconsciousness.
"Don't try to wake up. Our time is limited."
Sakura tried to speak, but her tongue felt like it was made of cotton. Her throat was so very dry; she could use a drink from Tsunade's fat mummy milkers.
"Nothing's going to come out of those withered sacks. Do try to focus, won't you?"
She groaned.
"You've instinctively sunken your consciousness into Breast Meditation to buy yourself more time. Listen to my voice, there's not much time."
Just as Naruto had never realised that his Shadow Clones were sharing their memories with him, Sakura had never noticed that Breast Meditation possessed a peculiar property: it touched upon the realm of dreams, where time had little meaning. A single moment in the waking world could stretch endlessly within the Spiritual Plane, where Sakura's soul could commune with the chakra imprints drawn from stolen breast chakra.
"Orochimaru…" Sakura rasped, as the underground lab within the dream swam into focus.
"The situation is dire," Orochimaru said, appearing before her as a hazy figure in a lab coat. "You are about to be fed to the Box of Paradise. There is no coming back from such a fate; not even Tsunade's Hundred Healings will save you from that."
Sakura vaguely remembered Katsuyu mentioning such a box in passing when discussing the subject of the demon Mōryō. The Box of Paradise was a terrible threat that had arisen in Kusagakure during the Sage of Six Paths' era. It was one of the many relics left behind by a Great Existence[Ōtsutsuki＝Shibai] when he had ascended to Godhood on this star, discarding His body and casting aside His possessions, and leaving them scattered across the shinobi continent.
"Mui tightened the Celestial Prison Seal," Sakura said in quiet realisation. "I can't knead any chakra."
But senjutsu chakra was another story entirely…
"Not even the esteemed Lady Katsuyu knows how ancient the Yin Seal is," said Orochimaru, his tone edged with reproach. "Your idea to alter it so that you could, as you put it, 'cheat out senjutsu chakra,' is not an easy one to realise."
"But you can do it, can't you?" Sakura replied hopefully. "You're a genius when it comes to jutsu."
Orochimaru smiled, the eerie curve of his lips never quite reaching his eyes. "With your help, perhaps. You underestimate your own intelligence. I've had a glimpse into your memories— and I must confess, I was rather impressed. Using the Yin Seal as your foundation, you devised the Breast Seal… a ridiculous name, but an undeniably effective jutsu, to be sure."
Sakura sighed. Even with the Prime AI gone, the System continued to cloud the minds of others who would intrude upon her thoughts, guarding its own existence from discovery.
"You know the Yin Seal much better than me; better than anyone, other than Tsunade," Orochimaru prompted. "You must have some idea of what must be accomplished."
Fūinjutsu was an incredibly complicated topic that Sakura had only briefly touched upon during her studies under Lady Tsunade, involving the intricacies of the true nature of chakra, painting yin and yang into circuit-like formations that could bring about supernatural effects from outside the body. But when the System had dropped the Breast Seal's information in her head, it had also given her the basics, so that she'd at least be able to activate her new ability.
"The Yin Seal itself has nothing to do with chakra, because it predates chakra itself," Sakura murmured. "The very core theory behind the Yin Seal is to excavate a metaphysical gap in one's cognition, thus the yin; pure imagination."
Before the advent of chakra, the Honoured Sages of Shikkotsu Forest used to gather nature energy in their mental energy seals. Thus, the Yin Seal's other name, Strength of a Hundred; sage power literally gave them the power of a hundred men.
"Go on," Orochimaru said thoughtfully.
"This is done by constantly gathering chakra at a single point on the forehead and layering it over itself in the shape of a diamond… but it doesn't necessarily have to be chakra," Sakura continued. "Anyway, when I first learned it, I kept going over the exercises Tsunade's imprint showed me, again and again for a week straight, until I could draw out and store chakra even in my sleep… wait— that's it!"
"For senjutsu, you would need a threefold Yin Seal; physical, spiritual and natural energies, releasing their energies into your system at an equal rate in order for you to 'cheat out' the 1:1:1 ratio," said Orochimaru pointedly. "Therein lies the rub: you are not even capable of achieving this simple ratio, so what leads you to believe that your powers of concentration alone are sufficient to divide your attention into constantly maintaining three different Yin Seals at once?"
Sakura smiled.
"But I'm not alone," she said. "I have everyone here, don't I?"
Orochimaru looked around. They were no longer in his dark laboratory, but standing amidst a sea of stars; each twinkling light a wisp of Breast Chakra containing a consciousness imprint. Some felt warm and fuzzy, while others burned with cold fury or seethed with dark grudges.
One by one, the warm lights grew brighter and flew closer, taking human form.
"Tsunade…" Orochimaru said softly.
His old comrade scowled at him.
"What are you doing inside my precious disciple, you perverted snake?" Tsunade snapped.
"I'm only lending you my breasts, got it?" Ino told Sakura with a huff. "I'm expecting them back soon… plus interest, got it? I need them to land myself a handsome man."
"We'll gladly lend you our strength, Sakura-chan," the neighbourhood grannies chorused. "You've always been a good girl."
The women's forms dissolved into wisps of light. Sakura caught them softly and drew them close to her bosom. The shimmering colours sank into her chest, merging with her two Breast Seals, then unfurled into slender bands of light that wound their way up her skin in twin spirals before coming to rest beside her original Yin Seal.
…
In the waking world, three crimson diamonds slowly began to appear on Sakura's brow, forming the shape of a lotus in bloom…