Mirror, Mirror (MLP)

>You screamed.
>A high pitched, girlish scream you didn't know you were capable of, but a scream nonetheless.
"WHAT THE FUCK DID YOU DO TO YOURSELF?!"
>"A, well, uh..." The stallion in front of you replied, not sure of what to say.
"Don't 'um' me, Twilight!" You shouted, causing the lavender stallion to recoil.
>"I just mastered a high-level spell!" He wailed, dancing back and forth on his hooves. "I thought you'd be proud!"
"Change yourself back!"
>"I...can't yet." His deep baritone echoed through the basement.
"Why not?!"
>"I need to research the counter-spell. One of Starswirl's books has it, I just can't remember which." The stallion said with a nonchalant shrug.
>You, meanwhile, were in full panic mode.
>You had been in the living room, relaxing with a book, when you heard an explosion in Twi's underground lab.
>You went downstairs to find a beefier stallion in her place, coughing from the ash and dust.
>It was then that you screamed.
>"Anon, it's not like I've changed."
"That twelve inch cock between your legs says otherwise!" You retorted.
>S/he looked, gasping in surprise.
>"Wow, I could put Big Mac to shame. I'm at least...ten and a half inches..."
>You facepalmed and went upstairs.
"I don't even want to know HOW you know how big Mac is."
>"I went over medical records, I swear!"
"Ugh."
>You stretched back across the couch, and Twilight followed suit.
>S/he flopped onto your chest, immediately knocking the wind out of you.
>You gasped for air, unable to breathe.
>Twilight had to have gained at least double her weight during that spell.
"T-T-Twi..." You gasped, patting the stallion on the side.
>"Hmm?" S/he said, looking back to you.
>The alicorn gasped, leaping off of you and winding you further.
>You spent the next five minutes catching your breath, Twilight looking at you with a guilty smile.
"No more...laying on me...until you change back." You said eventually, and with as much finality as you could.
>"Okay..." Twilight replied, ears down.
>"What about cuddling?"
"Jury's still out."
---
>You and Twilight had to go out for groceries.
>You were absolutely dreading it.
>"Hey Anon, who's the stallio-TWILIGHT!?" Rainbow Dash had shouted, and you sighed.
>Half the shoppers had turned to look, having reactions ranging from amusement to disgust.
>Twilight herself had grinned nervously and chuckled, picking out some things and paying for them.
>Dash was in hysterics.
>"Bwahahahahaha! Our local human's a COLT CUDDLER!"
>You ground your teeth to dust, willing yourself to not do the same to the cyan pegasus.
>The two of you made your way to AJ's stand, Twilight definitely embarrassed now.
>"Howdy you two...wait, who's th' stallion?" She greeted with arched eyebrows, having been far enough away to not hear Rainbow.
>You sighed.
"AJ. Wings. Horn. Star cutie mark. Who do you think this is?"
>"Oh mah stars..."
>AJ came out from behind her stand to look Twilight over, then went back behind her stand.
>To her credit, if she was laughing, she was keeping it internal.
>"W-well, this is quite the, uh, change."
>"I know, I know." Twilight replied. "We need to check the shelves when we get home, I know I have the spellbook there."
>"Better hurry Twi, you KNOW the Estrus season starts tomorrow." The mare reminded.
>You had completely forgotten.
>The two of you had, in fact.
>Twilight had a mate for the past two years, so she stayed mostly the same during Estrus, barring being a touch more...'receptive'.
"Oh no."
---
>Twelve hours later, the sun had set.
>Twilight had gone upstairs to research, having found the book she was looking for after tearing the entire library's shelves apart.
>As it turns out, the book she needed was on her nightstand.
>Spike was reading his comics, the occasional yawn showing the sleepy dragon was ready for bed.
>"Alright you two, I'm hitting the hay." He said, marking his page with a bookmark and closing the comic.
"G'night, Spike." You said.
>"Good Night Spike, love you!" Twilight called down.
>"Love you too, Twilight!" He called back, settling into his bed in his new room.
>His room used to be a storage room, but had been changed after you and Twilight realized the two of you had been keeping him up with your late-night antics.
>Now it was rather spacious, lined with bookshelves filled with comics.
>Pretty sweet digs, even by your standards.
>You went upstairs, marking your page and setting your book on the coffee table.
>"...I love you, Anon." Twilight said, sounding absolutely heartbroken.
"I love you too. Twilight, listen." You said softly, getting into bed. "I'm very, very proud of you for mastering this. This was just a shock to me, is all. I don't love you any less."
>The stallion nodded solemnly, still snout-deep in the book.
>You patted the bed.
"C'mon Twi, come to bed. We can cuddle."
>"I have to finish this research. Estrus starts tomorrow and no mare is taking my man but ME." Twilight said with a sudden fire, the very fire you remember from last year.
>Chuckling, you nodded and got up.
"Well, here, let me help."
>"Alright, here."
>S/he pulled down another book, opening it to a page.
>"Copy down all the ingredients I need for this."
>She highlighted a page.
>It was an anti-pregnancy drug, supposedly 100% effective.
>She used it every year, despite the species gap.
>You ran your fingers through his/her mane, it still smelled of lavender.
>S/he nuzzled into your side, leaning into you while still reading the book over.
>Yeah, still the same Twilight.
>You were ashamed of yourself for thinking that because her body changed, her personality did.
>What kind of asshole had you been today?
>'Massively close-minded' came to mind.
>Keeping up the soft mane stroking, you dutifully copied down the ingredients to a tee.
>It was a damn shame your 'door didn't swing that way'.
>"Anon, can you multiply that by six? My friends need some too...just in case."
>You chuckled.
"You sure Pinkie won't need more than one dose?"
>"No, it's effective all estrus season."
"Damn, we need some of this kind of contraceptive on Earth."
>A giggle that was two octaves too deep came from the stallion.
>He looked the book over for an hour, yawning.
"Twilight, you're dead on your hooves." You said softly, wrapping an arm around his shoulder.
>"Mmm...but...gotta finish..."
>With that, the mare-turned-stallion was out like a light.
>You picked up the significantly heavier pony with only a little more difficulty than before, covering her up and letting her sleep.
>You then picked up the book in her place, not truly knowing what you were looking for.
"Hmm...anti-gravity, she already knows that one...teleporation, she also knows that one..."
>You took a quick peek at the cover.
"High level spells? Really?" You shook your head in amusement.
>You searched for another two hours through the thick tome before finding it.
"Reversing Gender Spells; con't from Volume One...this must be it." You muttered.
"Reversal is simple, affected individual must merely submit to an act of carnal pleasure, willingly or not." You read off.
>Oh, was that it?
>Oh. That was it.
>Sighing lightly, and putting your apprehension to the side, you rolled your sleeves up.
>Looks like tonight, you were taking one for the team.
---
>You hopped out of the shower, feeling...less dirty than you thought you would have.
>Still, you were glad that stallions seemed to have absolutely no sexual stamina.
>You had managed to get him to cum in just about twenty seconds (shockingly long for a stallion), a simple handy being enough.
>What had really surprised you was the sheer force.
>Twilight would have to find a way to get the ceiling clean tomorrow.
>Caught you in the jaw too, hence the shower.
>You were glad to see that the book was right, though.
>In the stallion's place was now the cute mare you had known, undergoing the last bit of changes.
>Her snout was changing from that of a stallion's to that of a mare's, shrinking with some unpleasant crunching sounds.
>It didn't appear to hurt though.
>Her coat was stained with her own cum, but she was sleeping soundly.
>You settled in next to the mare, giving her a kiss on the neck.
"Good night, Twilight."
>"Good night, Anon...love you..." She replied, and it felt like lightning went through you.
"Yo-you're awake?
>"Mmhm...when something like that tears through my body, hard to stay asleep..." The still drowsy alicorn said, yawning.
"So...why didn't you say anything?"
>"Felt too good, thought you'd stop if I said something."
>You chuckled, there were times you had done that to her.
>She'd occasionally give you a 'stealth' blowjob in the middle of the night, you'd wake up and say not a damn word.
>She'd stop otherwise.
"Fair enough."
>She snuggled into your chest, smelling you.
>"Mmm, you used that shampoo I like..."
>She was getting a little 'gropey' now, not that you minded.
>Estrus was the one time she lead and you followed.
>Thankfully, she was far too tired to do much more, falling asleep into your chest.
>The slow rise and fall of her back was hypnotic, and you found yourself soon asleep as well.
>Sleep wouldn't last long, and you knew it, but for now...it was enough to have your mare back.
"Love you, Twilight."