Celestia shuddered, a gasp tumbling from her throat, her cheeks flushed as she kicked at the air with her hooves in helpless delight. The alicorn’s wings flexed, flaring and relaxing in repeated spasms as her back arched in fitful bursts of ecstasy.
The Princess was being loud. But she couldn’t help it! Soft little squeals, gasps, and giggles left her as Twilight went about her naughty work so eagerly, even occasionally using her tongue to make the constantly-composed Princess quiver and shudder in reflexive spasms.
Twilight grinned up at the Princess as she worked, letting her hooves rest at the Princess’s side to help hold her steady, and to maintain her position so the flailing limbs of the alicorn didn’t dislodge her or cause her injury. The librarian’s horn was glowing, aiding in small little rubs and caresses to further entice the Princess.
Celestia for her part could barely breathe. Her chest rose and fell in rapid rhythm and her breathless protests fell on deaf ears. Her usually elegant mane and tail were crumpled beneath her, mussed up and tangled. But Celestia was far from caring at that point, too enraptured in what Twilight was doing to her.
The faint squeals she was making, however, did not go unnoticed by the castle guards. They shifted nervously in place. The first time they’d come rushing to the Princesses aid, they had been ordered straight back out by the red-faced alicorn. After that, they never entered unless explicitly called for; at least when it was Celestia and Twilight alone in the rooms.
A third party, however, had already arrived.
Princess Luna was striding down the long halls, elegant blue mane and tail trailing behind her as blue eyes regarded the pair of nervous Royal Guards outside of Celestia’s room.
The dark princess paused in front of the two guards, and turned towards the door. A pair of spears blocked her entry.
“What is the meaning of this?” she asked in a low, affronted tone.
“The...uh Princess is busy, yeah,” one of the guards said quickly, refusing to meet her gaze.
“Really busy,” the second guard added, clearing his throat and straightening. “Not to be disturbed. Nope.”
Luna huffed, raising a hoof to declare that they allow her to pass, before she paused. One of her ears pricked, and she turned her head to the side, leaning in until her head was almost touching the door.
The two guards exchanged alarmed glances.
A soft squeal met the Princess’s ears, and then a stifled cry of ‘N-no, s-stop!’.
Eyes widening, Luna reared up on her hooves and then slammed them both into the centre of the door, sending the large double-doors exploding inwards with a heavy crack! and a shower of wood splinters.
Immediately, the two ponies inside, Celestia And Twilight, disentangled from eachother and bounced to their feet to stand awkwardly, side-by-side, like two foals caught with their hoofs in the cookie jar.
“What is going on in here?!” came the demand from the smaller of the two Princesses, her gaze flicking from guilty face, to the other. “We demand to know!”
Celestia splayed her ears backwards, looking to Twilight, and then back to Luna again uncomfortably, her cheeks flushing faintly as she stuttered, “I-it’s not what it looks like, s-sister.”
Twilight looked at Celestia, and then to Luna, a slow grin spreading across her face as she affected her most innocent of smile. “But Princess...How do we even know what Luna thinks it looks like? I mean, it was just you, on your back, face all red, squealing, with me on top of you...” she trailed off suggestively.
If it was possible, Celestia went even more red in the face, her eyes widening at the implications, turning to Luna to try and explain, spluttering in her fluster, “T-that’s not true!”
Luna’s eyes narrowed slowly on her sisters, her tone accusing, “And here we were, thinking that it looked like Twilight was atop your form, making you squeal like a filly!”
The white alicorn flustered even further, her ears splaying backwards, “B-but I...that’s n-not!...”
Twilight spoke up again, her innocent smile firmly fixed in place; “Oh Princess. You should just come clean. I mean, your sister knows your dirty little secret now...or she’s guessed what it is,” she said with an earnest nod, her tone gentle and soothing in a completely teasing manner.
Celestia’s eyes widened, her mouth parting slightly in a stunned expression, turning to look at the cold expression of her sister, shaking her head helplessly. “No! That’s not it at all!”
“Then what is it, dearest sister?” Luna asked coldly, scowling.
“Oh, it’s exactly what you think.” Twilight confirmed, cutting over top of Celestia’s next response. “I didn’t want to do it, not at first...but Celestia corrupted me...” the young unicorn put on the saddest face she possibly could, to look young and vulnerable.
Luna’s expression was scandalous as she rounded on her sister, “You corrupted Twilight?!”
Celestia tried to cover her face with a hoof, the entirety of her expression a deep red. “I-It’s not my fault! S-she starts it half the time now!”
“That is hardly the point!” Luna stated, stamping a hoof on the ground hard enough to crack stone, her eyes narrowing. “How do you intend to explain yourself, sister?!”
The young unicorn stepped over closer to the dark Princess, smiling wanly as she whispered; “She even makes me use my tongue!”
Luna stared at her sister, wide-eyed, slack-jawed.
Celestia spluttered faintly, unable to hear what Twilight had said to her sister, rapidly losing control of the situation. She lifted a hoof, pointing it at the door with the command, “Twilight, leave!”
Grinning innocently, the young unicorn pranced to the door, and paused to look over her shoulder for a moment. “She’s just gonna try corrupt you too, Luna!” she sing-songed, before bouncing happily out the door, closing it after herself.
A cold silence filled the room while Luna stared at Celestia, and the white alicorn refused to meet her gaze.
“Do you have anything to say for yourself?” Luna asked coldly.
“It’s not my fault.” Celestia whined, ears pinned back, cheeks flushed deeply.
“And how, praytell, is that possible?” she demanded.
Celestia looked away again, staring at the floor somewhere to her right. “I-It was an accident at first.”
Luna gave a faint nod, to encourage her sister to continue.
“It was a game, really!” Celestia added.
“A game?” Luna asked, scowling. “That is hardly a game!”
“But you don’t understand!”
“Then explain it to us, Sister.” Luna scowled in response, eyes narrowing.
“W-well. I was teaching Twilight a levitation spell. And she tried it on me, as a game. But she kind of lost control...and I sort of...maybe kind of fell on her.” Celestia said in a very, very small voice. “A-and...she was well...squirming a lot...”
Luna just stared at her for a long moment, her eyes wide, shaking her head slowly from side-to-side.
“I-It’s not what you think!” Celestia protested again, her voice rising.
“We think it is exactly what we think!” Luna countered immediately, eyes narrowing.
“I’ll show you!” Celestia said, rising to her hooves properly, her gaze hardening on her sister.
Luna blinked once at the change in attitude, and Celestia’s words took a few seconds to register fully; a precious few seconds that her sister used to get in under her guard.
In an instant, Luna felt her limbs immobilised. She tried to use her own magic to counter it, but she was trapped. Her gaze turned fearful, even as Celestia stepped over to her. She swallowed hard. “S-sister. W-what do you intend to d-do?”
Celestia gave her a long stare, and her horn glowed more powerfully as her sister was lifted in the air in front of her, the magic tugging her limbs out in a splayed position in front of the white alicorn. The princess just shook her head sadly. “I’m going to show you.”
Luna tried to struggle, but it was too late; her sister was upon her!
The white alicorn set to with a will, burying her nose right against her sister's stomach, hooves lifting to grip at her sides and dig in just enough to cause a ticklish, light, rasping sensation, even as she began to rub her nose back and forth in firm little flicks, just like Twilight was far too adept at for her own good.
Luna struggled all the harder, her eyes widening and her limbs twitching as she tried to contain the giggles bubbling up in her throat, helpless under the onslaught of her sister, the tickling hooves at her side and the nose rubbing against her so ticklishly.
Celestia grinned up at her sister mischievously, and then drew back, blowing a hard stream of air over the dark alicorns stomach and then leaning in to give a firm, rapid lick from one side to the other, making her sisters stomach muscles spasm reflexively as she squirmed and struggled.
Helpless, breathless giggles began to roll from Luna’s throat as she tossed her head back and forth in a vain attempt to escape the tickle torture her sister was so expertly meting out upon her form. But there was no relent from the onslaught, until she was light-headed and limp, panting breathlessly, still squirming slightly as she was lowered gently to the ground.
Luna stared up at her sister for a long moment, trying to catch her breath. “We do not think that was fair,” she growled after a moment.
Celestia shrugged, and poked her tongue at her sister with a giggle, turning away.
With a war-cry, Luna pounced on her sister, rolling the large form over and over until she could splay herself atop her in victory, attacking her stomach with hooves and muzzle, rubbing and tickling vigorously to earn recompense for her previous torture.
Twilight watched from the doorway, smiling innocently.
“Told you she was going to corrupt you.” she said with a smile, turning away.
