>*thud*
>Celestia snapped from her dreary, officiating letters and edicts and jumped to her hooves
>on turning saw her sibling galloping to her, naked of her usual regalia and panicked
>”Sister! I need your aid,” Luna said.
>”It's rare to see you this early in the day,” Celestia chuckled, then turned serious. “What's wrong?”
>Luna skidded to a halt before Celestia, who frowned in response as she noticed what was wrong, but was too confused by what she saw to speak
>Impatient, Luna pleaded, ”tell me you see it, sister! I'm... bigger.”
>getting her senses together, Celestia replied, ”w- well, that is somewhat to be expected, Luna. Your exile did arrest much of your physical development, and I'm sure you will catch up to my size in time, akin to your form as Nightmare Moon, but-”
>both sisters gasped, but Luna grunted, her body twitching as they watched Luna's legs stretch longer, her whole body swell out, and her eyes go wide as she sprouted up a whole foot taller
>Celestia blinked, jaw agape, as Luna was now eye-level with her chin
>”That's not...” Celestia started, then stroked her chin with a foreleg. “Hmm, I wonder...”
>”What? What is it?” Luna paced about, her heavier hooffalls causing a deeper clopping than she was used to. “Do you know what ailment is befalling me?”
>”Maybe,” Celestia said and bit her lip, but then shook her head. “Come, I need to brush up on something.”
>with a flash of her horn, the pair teleported into the hidden section of the Canterlot library
>”Many centuries ago,” Celestia said, and sighed, “not long after our... falling out, I underwent a transformation of sorts. A blossoming of my powers. I had assumed it was where I was having to undertake your duties, but the events that took place were anything but ideal.”
>she led her younger sister to the dusty table, and pulled a simple looking book from a high shelf with her magic, then opened it in front of them
>the pages depicted, in words and simply drawn pictures, the tale of Princess Celestia
>and the time she had to leave her people for a time, not unlike Luna's banishment
>the reasons were even similar, as Celestia had become too dangerous to remain
>but Luna gasped at the details
>the picture showed the world, as understood back from that time
>and beside it, Celestia, almost as large, dwarfing the landscape
>”My powers grew exponentially stronger by the minute,” Celestia continued, “and just as all alicorns grow as they age, all that power had an affect on me that-”
>Luna yelped as, once again, her body trembled
>her hooves scraped the ground as they both enlarged, but also spread wider on the aged stone floor
>and her height swiftly caught up to Celestia, then surpassed it
>with a final surge, she panted and winced as the alien sensations left her a clear two feet taller than her sister
>Celestia gulped, and finished, “led me to grow so truly vast, that I had no choice but to flee the land.”

>”B- but you know how to put a stop to these spurts, yes? You are a colossus no longer.”
>”There is no cure,” Celestia said, and placed a gentle, reassuring hoof and wing on her sister's shoulder. “I simply waited until my body could control the sheer magnitude of the flow of magic within, and I shrank back down over the span of a few days.”
>”Then the matter is settled,” Luna said, putting on a brave face. “Banish me, as needed. I endured for so long as the vile Nightmare Moon, that I can withstand another week.”
>”It isn't as simple as that, Luna,” Celestia said. “The magic within you also manifests from the love and adoration of our subjects. Each pony instils power within us, and without their presence, your growth will take far, far too long.”
>”Are you suggesting I remain and potentially harm them as I grow unstoppably larger!?”
>”For at time, I fear so,” Celestia said with a nod. “It could be years without their influence. Besides, the bigger you are when we eventually send you, the less time you'll have to spend alone.”
>”I fear not the solitude, Tia, I just... damn it!”
>both watched as, once more, Luna grew, much to the younger sibling's discomfort as she screwed her eyes closed and trembled
>Celestia paced backwards and into a bookshelf as Luna began to dwarf the room, her ever longer legs pushing the table away as the monumental growth spurt outlasted both prior ones she had witnessed
>it was only when Luna's horn struck the twenty foot ceiling that it stopped, as the moon goddess opened her eyes and squeaked in shock
>Celestia looked down at where she stood, at the narrow space between her sister and the wall, but then grinned, which turned increasingly impish. ”You know, there might be a way to hasten your growth far faster than I had to endure. Not to mention, we are in need of more space for you to reach your full splendour, and the venue is outdoors on this evening.”
>”Anything, please” Luna pleaded as she glanced at the low ceiling, “I am beginning to feel claustrophobic!”
>with yet another flash of yellow magic, Celestia teleported them to a late evening sky, an open field
>and a large, vocal crowd, suddenly hushed
>”... and this evening promises a truly magnificent moon, and-” a voice called out on a megaphone, then gasped. “We've been blessed by special guests! And our mistress!”
>the crowd collectively 'ooooh'd'
>Luna balked at the massive social gathering, turned to Celestia, and whispered, “what is this occasion? Where are we?”
>Celestia couldn't stop from snickering. “Oh, this? I heard of a little get-together of star watchers who enjoy observing the celestial bodies, especially the moon and its mistress.”
>Luna's eyes widened. “Y- you mean the Luna Appreciation and Star Spotter's society? The ones we had to ban because they kept trying to disturb my nightly duties?”

>”Oh yes, them.” Celestia beamed a grin. “They didn't do anything wrong, exactly, and I've always felt guilty about your envy of my subject's unconditional love, so I've encouraged them to just worship you from afar,” Celestia said, then addressed the crowd. “Good evening, good mares and stallions of Luna's A.S.S society!”
>”Now, just one moment, Tia, I-”
>Celestia continued, “on this day, as the harvest moon rises this eve and in celebration of your dedication, I present to you my dear sister, Princess Luna! Take a bow, sis!”
>Luna's blush turned her deep blue cheeks a burning red as the crowd went wild
>magic crackled through her body as the fans showered her with adoration, praise and more than a few wild screams of a... less appropriate, more lustful
>the effect was immediate as Luna's body rumbled, her eyes glowed and with a yelp, she grew
>even Celestia was taken aback as she was knocked aside by one of her sister's hooves, which dragged through the soil like a gigantic, ever bigger plough, as Luna hit thirty, forty feet at the shoulder
>she thought to beg for them to stop, but to her own surprise, the growth began to feel good... even great
>”Yes,” Luna moaned. “Praise me! Worship me! Make me bigger!”
>Celestia blinked away, and began to lower the sun, even as Luna's rampant powers raised the full moon, and even that began to glow with an intense white light
>the cheering crowd didn't stop as the ground shook as hooves wider than redwoods continued to crash through the surroundings, shattering boulders
>to spare the crowds, Celestia lifted the gathering, which had to be a hundred dedicated (if not obsessive) ponies, and teleported them one by one in a rapid set of flashes back to Canterlot
>but their dedication was still only a drop in the ocean, as Luna soon came down from her growth induced reverie, now easily a hundred feet tall at the shoulder
>Luna shook her head, her flowing, starry mane swishing about before it returned to its unnatural flow, and she bit her lip as she stared down at the landscape
>even adjusting her position with a gentle tap of her hooves made the ground quake
>invoking the royal Canterlot voice, Celestia bellowed, “looking good, Luna!”
>”DID THIS- oh, excuse me,” Luna first bellowed, then whispered, still in a booming voice, “did this feel as good for you, Tia? It's... quite distracting. I feel I might need to deal with it before too long.”
>Celestia teleported onto her sister's snout and, in her regular voice, said, “it really is. That cubby within which Canterlot was built? Let's just say when I had my 'blossoming', that crevice didn't exist. Also that jokes about my admittedly respectable posterior were born from precisely that moment.”
>Luna snickered, and replied, “you mean to say that you ground out the platform of your new palace with your rump?”

>Celestia nodded, and though she kept her composure, blushed at the memory. “I recommend doing the same before you resume growing, to clear your mind. As word and view of your enlargement spreads, and more ponies begin thinking of you, the larger you will grow, and the quicker they will happen. Once you get big enough, you'll be hard pressed to find any real satisfaction.”
>Luna pouted, and was glad her horniness was suppressing her modesty. She eyed the mountains that housed Canterlot, and sighed. ”Hold fast, sister, I shall find a more secluded spot.
>Celestia lowered herself and balanced with her wings as Luna took her first step
>she planted her hoof down, and gasped as the ground cracked and split, an impact shockwave spreading from just one step
>”Uh, sister?” Luna asked. “How does one walk without causing undue devestation?”
>”You don't, or rather, can't. Just watch where you plant your hooves and get it over with. Try not to worry!”
>”If you insist, Tia.”
>another step, another rumble of the land, another crater
>Luna abhorred being a spectacle after her... interesting reintroduction during the Nightmare Night event in Ponyville, and the guilt of her past misdeeds continued to colour her opinion of herself
>but something about this feeling... this power...
>Luna smirked, raised a hoof and looked closely at the ground to make sure nopony was nearby
>she then slammed her hoof down, and marvelled at the shockwave as it spread like a cloud from the impact
>it made her giddy, and Luna couldn't help but grin
>”Ah, you've reached the curiosity phase,” Celestia mused.
>”We already must tread on tender hooves around our subjects, but to have so much raw power is intoxicating, even beyond the... energetic feeling betwixt my flanks.”
>Celestia nodded to the mountain. “You might want to hurry up before you begin winking then; I imagine you'll give your A.S.S followers, Canterlot and most of Ponyville quite the show otherwise...”
>Luna flushed and cleared her throat. “Point taken.”
>”... however small the A.S.S may seem, proportionally speaking.”
>”Tia, another word about my *perfectly sized and pert* rump, and I shall put you beneath it!”
>Celestia giggled and bowed. “Pay me no heed! This is your day.”
>Luna sighed, finished her approach to the mountain, and turned about
>she was keenly aware that she was likely visible from Cloudsdale and Ponyville, and even portions of Canterlot, but the tingling beneath her tail was becoming too much to ignore
>so she pushed back against the mountainside, and began feeling about
>too flat... hmm, too jagged
>Luna tried to ignore the sound of crumbling rock as best she could, then finally...
>”Mmmhh!”
>a long, smooth jutting rock

>she backed herself onto it, and her inner muscles began to gently work itself against the little edges, the stiffness and length
>being a princess was a lonely affair, even more so as the unapproachable goddess of the night, and she had long since suppressed this lewder side of her
>but it came gushing forth; her moans reverberated through the air
>she could feel the eyes of Equestria turn towards her as she gasped and whimpered in bliss
>and as she felt their attention, their admiration of her gigantic form, the buzzing magic within spiked
>it energised and caused her to scream out so loudly, the moon once more burned so brightly, that everything was a blur of noise and light
>the unyielding stone... yielded, and her inner muscles clenched, crushing the stone, and she fell back onto the mountain, taking out a large chunk of the slope
>and she climaxed as her growth spurt once more fired up
>her fluids gushed down the mountainside, washing across the road as she stumbled away and the pulverised stone fell free of her slit
>and with a triumphant laugh, Luna blossomed ever bigger
>the mountain was soon matched by a two hundred foot tall Luna
>three hundred
>”More! Bigger!!”
>five hundred feet
>the ground rumbled from her dazed pacing, and the whole of Equestria could likely feel her bliss through her titanic hooves as she continued to ride her orgasmic high
>each hoof slamming down was louder and more destructive than the last
>and when she finally recovered her senses, Luna's eyes went wide
>Canterlot wasn't even up to her knees
>”Oh my,” she whispered, and watched as even that tiny utterance sent clouds billowing away from her
>her every action was catastrophic to the world
>and she narrowed her eyes onto her snout, and could barely see the tiny white speck on it
>Celestia bellowed, again invoking The Voice, “I think it's time we made one final show, then we'll send you to finish blossoming.”
>”Am I not vast enough?” she said, barely breathing the words. “Much more and I fear the face of Equestria will be permanently damaged!”
>”Oh, it's not so bad,” Celestia said. “We already get places dedicated to us, and the mountain's already been given a lasting mark. Live a little, Luna!”
>Luna grumbled and once more observed the massive, violent explosions of force her hooves were causing
>rock, dirt and trees being blasted away from each impact
>much of the fun of her immeasurable size and power was beginning to worry her once more
>”So what is next?” Luna asked
>”Now you simply need to unleash The Voice, and let our subjects know you mean them no harm, and to draw their admiration.”
>”B- but Tia, won't my voice alone cause undue damage?”
>”Like I said, you've already left an impact. Own it! Leave them wanting more, and you'll reach heights the likes you'll not believe!”
>Luna stopped, pondered, then took a deep breath as Celestia crouched low, then covered her ears with her forelegs

>”Citizens of Equestria!!”
>the wave of sound from her mouth rippled the air, and Luna winced as even Cloudsdale was knocked back by the blast and destroyed several of the taller buildings
>”They'll be fine,” Celestia said. “Just maybe don't talk towards the city? But hurry, because everpony's going to be looking at you now.”
>Luna nodded, faced upward, and announced to the world, “forgive the brusqueness of my announcement, but this is Luna, your Princess of the Night! Your acceptance of me, despite my past transgressions, shall always fill my heart with joy! And now that I am ascending to greater strengths and loftier heights, know I shall dedicate myself ever more to protecting you all! Thank you!”
>”Not bad,” Celestia said, “I would have openly invited everyone to observe just how large your butt is at this size, but not bad.”
>”Tia, I swear, I-”
>then she felt it
>once more, the power inside Luna surged, and she trembled
>this was going to be it
>as every pony, and even those from farther afield observed her magnificence, or at least heard her words, everyone now had Luna in their thoughts
>this was when Luna would ascend
>”It's time,” Celestia said as Luna's snout grew beneath her. “Let me muster my magic to send you beyond our world. But before I do, I just want to say how proud I am.”
>Luna, as hundreds of feet evolved to a thousand, breathed, ”T- Tia?”
>”To come back to me, to flourish and take on your responsibilities, to grow beyond such trauma and strife. And to just be my precious little sister. Know that, even if I seldom have the chance to say the words, you are the best sister anypony could ask for. Know that I love you with all my heart.”
>tears the size of villages leaked from Luna's eyes. “Thank you.”
>”See you on the other side.”
>with a brilliant flash, the light of the moon remained, but the ambience was far darker
>and Luna was adrift above the world
>she marvelled at the vastness of the planet, and saw Equestria's landmass, and waved a hoof
>and as their gazes went skyward, Luna relaxed, and let herself grow, and bloomed
>the vast sphere of her domain, the moon itself grew with an intense light alongside the goddess
>and the world dwindled, rapidly, as thousands of feet gave way to tens of thousands
>it was less base pleasure now, and more enlightenment, to become one with her own power
>Luna felt at one with everypony, and everything, and grew even faster
>the sky was aglow with her dark blue coat as her very being filled with energy and filled the sky for the ponies below
>and every single being admired her every curve
>she turned and wiggled her behind, and the stray strands of her ethereal tail glanced against the atmosphere, smouldering with luminescence
>Luna, the True Goddess of the Night, was born
>the benevolent, comforting, all enshrouding darkness

One week later
>”Are you prepared, Luna? The public awaits.”
>”Almost, Tia, just.... tsk. Are you certain this new regalia was made to my exact measurements? T'is a bit tight.”
>”It's supposed to be. To show of that glorious body of yours, sister. You'll drop jaws and fill many a dream this night!”
>Celestia stepped out of Luna's room
>closely followed by the younger, yet now bigger, sister, who stood a full head taller, in form fitting royal attire
>she had also apparently kept more than a few pounds in the right spots; her flank was fuller, and body just a bit thicker all round
>”I suppose I spent most of a thousand years looking up at you upon the moon, but now once more in the flesh is a more welcoming experience.”
>Luna smirked. “What can I say? Your love was to blame. A worse sister wouldn't have made me quite so resplendent.”
>”And such resplendence comes new responsibilities,” Celestia said and playfully bumped against her sibling
>Luna pushed back, sending Celestia into a stumble. “I am ready.”
>and the ascended Luna walked beside her dear sister, to a new age
The end.