It had been a thousand years since she’d eaten cake.
Or, you know, eaten.
The Newly-Returned Princess Luna tried to be polite as she stuffed her face with everything the servants would bring in front of her. The raucous celebration taking place in the dining hall of Canterlot helped hide the princesses somewhat obscene indulgence - as did the beaming presence of her beloved sister.
It had been an age since they had sat together happily and watched their subjects revel and feast. Only that day had Luna been saved from her madness, only that day had the sisters gotten another chance. They had had almost no time to speak with each other since then - which was fortunate, because Luna felt too weak for Royal Canterlot Voice, which was required of her when she spoke in public. Instead they had let the ponies of Equestria rejoice that Luna was no longer evil and partake of the provisons they had set for the Summer Sun Celebration.
But slowly, the ponies energy faded - though it was far past midnight, so even Luna couldn’t blame them - and they departed one by one, soon leaving Celestia and Luna alone.
Alone did not mean without pie.
Now that they were out of the public eye Luna simply stuck her snout in a large blueberry pie and devoured it noisily, splatter flying onto her mane and the tablecloth. She heard her sister laugh a lighthearted laugh besides her as Luna levitated the tankard of wine over and drained it.
With a belch she set the cup down and with a sigh she sat back.
“ Ooh, sister, you do not know how happy I am to be back.” said Luna, her eyelids drooping as the soothing food began to digest. She poked her slightly swollen tummy with one hoof and giggled.
“ And sister, you do not know how happy I am to have you back.” said Celestia, nuzzling her - and smearing the blueberry filling a little. Then, to Luna’s confusion, Celestia’s horn glowed with magic and the doors and windows sealed - a mighty ward had been put up to keep them absolutely alone.
“ Sister, what are you doing?” asked Luna, sitting up and looking around.
She was then pounced by her Celestia, who pinned her to the ground and let out a great sob.
“ Oh, Luna, you’ve got you help me! Everypony in Equestria’s gone gay!”
“...so...I guess I should start at the beginning.” said Celestia sheepishly, letting out a small hiccup as she downed a snifter of champagne.
“...yes.” said Luna, still to stunned to react properly. She’d just spent five minutes consoling her gibbering, sobbing older sister - there were still wet tears on Celestia’s face and Luna’s mane. With red, mournful eyes Celestia looked to Luna with eyes that begged forgiveness.
Luna was deeply confused.
Shouldn’t she be the one begging her sister to accept her apology right now?
And what was wrong with everypony being gay? They’d had a gay time that evening and Celestia had enjoyed it! To abuse the word, they’d gaily danced, drank, sung, eaten, and talked with zest! Luna could hardly remember a gayer evening in her life!
“...it starts after I banished you to the moon.” said Celestia, looking into her drink. “ I was ... lonely. And I admit I sound many escapes. I drank, I reveled, and all the normal things...and I also started taking on the form of normal pony mares and seeking more...base comforts.”
“ ...base?” asked Luna, confused. “ Sister, what could you mean?”
“ I had a ton of sex.”
Luna blushed a deep red at her sisters statement. She couldn’t believe her ears - her sister having - no! She wasn’t thinking about that! THE ACT could not be applied to her sister. Luna hadn’t even partaken herself, leaving her far from ready to deal with her sisters - WHOOP DON’T IMAGINE THAT.
“ To be clear, I must be banal.” sighed Celestia. “ I must lay claim to pioneering roughly nine-tenths of the acts, techniques, and fetishes that have been invented in the last thousand years. The normal way...got old. I experimented, I tried new things, and, well...they worked. For a while.”
“...new things?” despite herself, Luna couldn’t help but be a little interested.
“ You know where it goes?” said Celestia nervously. “ Uh, well, one time...a stallion missed.”
Luna’s flank-cheeks clenched together and she threw up seven magical barriers.
“...and, well, a while later I thought...you know, it’s basically the same thing...and if cleaned out, who knows?”
“ Sister, this is either the most profane jest or - or - !” Luna couldn’t finish her statement, instead choosing to down another flagon of ale. She’d need it soon.
“ Then, later, well, I figure, I’ve another orfice...” Celestia said with a nervous chuckle. It took Luna a moment to count.
The ale sprayed all over Celestia.
“ I won’t get too graphic...it gets...worse.” said Celestia, magician herself clean as Luna gibbered and gagged in horror. “ But, there reached a point where, well, um, I’d done everything a mare could do. And I thought back to Starswirl the Bearded’s Aniomorphic spell, where he’d turned himself into a mare for an hour...”
Luna tossed the ale away and levitated over the stouter stuff. She poured herself a flagon, downed it, and desperately tried to stop imagining Celestia with a penis.
“...but here I met a snag. I wasn’t...interested in mares. And I couldn’t...you know...get it going. So I made a simple little spell to change my preferences as well as my body and went back to it.”
She downed her champagne.
“ And whoo, did I do it.” said Celestia, her eyes going unfocused for a moment as she licked her lips. “ But something odd happened. When I ...I’ll be polite and simply say “finished”, the spell seemed to transfer. It didn’t affect the ponies right away - in fact, it took three generations to start having effect. But it also spread to everypony that they mated with. And again from the new infectees. And eventually, it was simply incorperated into the natural magic of Equestria.”
“...but...what does that have to do with the citizens being gay?” asked Luna, trying to change subjects.
“ Nowadays, gay means interested in members of ones own gender.”
Luna blinked.
There was a minute of silence.
“ ...and, well, it’s spread so far...that I’ve had to keep Equestria...fertile...somewhat manually.” said Celestia with a weak grin and a nervous twitch. “ Charm spells between mares and stallions strong enough to beat the gayspell...clinics where mares in gay relationships could be impregnated with semen collected from stallions...and, well, as you might have noticed with the Royal Guard...”
Luna chocked on her breath as she realized it wasn’t that Celestia chose pure white stallions for her guard - she’d PRODUCED them herself.
“ ... and I can’t figure out any way to break the spell.” concluded Princess Celestia, giving Luna a furtive look. “ At least, but one way.”
“...I’m not going to like this, am I?” asked Luna with a grimace.
“ Well, if one of us completely absorbed the spell...it would go away. But...to tell the truth, that would ruin thousands of relationships. There was a point some years ago where the rate of homosexuality in ponies was actually highly useful in maintaining population balance...so, if we decrease it back down to there over, say, a year...”
“...sister, you can’t be planning to saddle me with a year long task the moment I return home.” Luna begged. “ Couldn’t you do this while...I...ruled... a nation I know nothing about.” she sighed as she realized that it was a better option for her to do it than Celestia. “ ...I see, now. I will do this.”
“...there’s another complication.” said Celestia tenderly. “ I think it would leave you what we call “bisexual” these days. It means interested in both genders. And, well, there is a little issue with the spell making you somewhat more randy.”
“...how randy?”
“ Hmmm....permanently interested with spikes of super-intense lust that can only be sated by a squad of burly hoofball players, the cheerleaders, and anypony who might pass nearby.”
“...what if we go half-and-half on this, sister.” said Luna, eyes narrowing. “ Tis your fault, not mine. Would that perhaps weaken the...power?”
“...maybe...” said Celestia gingerly. “ In any event, it would be...more fair.”
“...then I guess I will begin after the sun rises.” said Luna, rising to her hooves and standing. “...pray tell, sister, does Batwing Syndrome still affect pegasi?”
“ O-on occasion.” said Celestia, looking confused but relieved.
“ Find several dozen. Have them recruited as my royal guard.” said Luna, letting out a long sigh. “ If you’ll excuse me, sister...I guess I am going to go sleep alone. For the last time. Ever.”
“...you won’t miss it.” Celestia said with a coy little smile, rising and nuzzling her sister in thanks. “ Trust me.”
“...so tell me, sister.” said Luna as the two alicorn walked towards the exit of the hall, the wards falling as they approached. “ What are “fetishes”?”
“...you know...like socks.”
“ OH, EW!”