“Try to relax, my student,” a voice whispered into Twilight Sparkle’s right ear. The purple alicorn tried, but to obey was much easier said than done.

Twilight had a hunch that her first mission as an alicorn princess - her real first mission - would involve what she’d learned months before. Not what she’d learned about friendship - her trip through the mirror was a happy accident - but what she learned before that, before she and her friends rescued Shining Armor from the sticky-sweet embrace of Queen Chrysalis, then used the Elements of Debauchery to fuck the changeling into submission on the floor of the Canterlot chapel.

It was time to revisit what she discovered when she peered between the musky covers of Applejack’s magnum opus, “The Goddess Within.”

Sure enough, here she was, lying in Princess Celestia’s lap on the matriarch’s plush Canterlot bed, both of them up well past their bedtime.

The still fully-grown Spike had belched out the letter in the middle of the night, and he rushed over from Zecora’s hut to the rebuilt Ponyville Library to deliver it. The muscular dragon wanted to go with Twilight, but the letter expressly prohibited anyone from coming along. It was just as well. Spike was now married to the beautiful dragoness Zecora, and Twilight needed somepony to help her husband watch Charming Thunder, her little black unicorn foal, now sleeping in Spike’s old bed.

Twilight hoped to be back in time for their play-date the next morning - after all, she was not just a mother, but a married mare, just like her friends. Just like everypony else she knew. Celestia had made sure of this by royal decree. On pain of banishment, every foal birthed from the Fall Weather Orgy was accounted for, and the parents were married in mass weddings in order to provide them a home. In some cases, such as Cheerliee’s, this meant marrying several stallions - and young ones at that. Celestia had done all this in short order, transforming Equestria once more. And Twilight knew Flash Sentry was waiting for her to come back to bed.

But still, Celestia wouldn’t let her student go.

“I’m sorry—” whimpered Twilight, her crown sliding against her horn. Celestia nibbled on her right ear once more, then gave it a gentle lick. Twilight’s body quivered once more as she felt Celestia’s hooves melt into hands between her purple thighs. “I’m sorr–unh!”

The two alicorns grew again, and Twilight’s purple wings flapped briskly against Celestia’s large white breasts. Celestia leaned her head back, stretching her long torso, taking a deep breath of the scent that puffed up between them.

Something tugged Twilight’s tail. Celestia’s thick white cock, ensnared in the long purple-and-pink hairs, was yanking it with every throb. Twilight had yet to see it - the matriarch refused to let her see her own changes - but she could feel it, her purple body rubbing against its hot, pulsing shape.

“Mmm–unh—” murmured Twilight.

Transforming was even more intense than Twilight remembered - with all her new royal and motherly duties, she had yet to have a chance to embrace her goddess form in her new alicorn body. It was somewhat of a relief when she was transported to the human world, but she was disappointed that her human marehood proved far less satisfying to touch than her beautiful purple pony pussy. In that world, it didn’t feel as good as this. Her purple clit felt like it was growing to her teacher’s touch, her white fingers wrapping around the resulting protuberance.

Then Celestia squeezed her clit.

“Uhn—Unh!” cried Twilight, her breasts fattening in the glow of the full moon.

“I’m not finished with you, Twilight,” Celestia purred into Twilight’s right ear, making it twitch. To drive the point home, Celestia pushed her thumb on the tip, letting its swollen shape throb between her fingers.

“Unnnf!” Celestia stuck her tongue inside her student’s ear.

“You may be married. You may have a family of your own,” said the white pony, “but you still belong to me.”

The more Celestia rubbed her clit, the heavier it felt, and the more sensitive it became. Celestia kissed the nape of Twilight’s neck. Her left arm grabbing behind her for Celestia’s shoulder, her left hand still caressing her own thigh, Twilight watched as Celestia’s hand guided her dark purple cock into view for the first time. It was big - the biggest she’d seen yet. It looked almost fearsome, its spidery black veins throbbing with life over two hard ribs.

“You’re not a normal mare anymore. You’re like me. And you will do as I command.” Celestia kissed Twilight on the cheek and her student’s cock bucked toward her, shoving her white wrist closer to her belly.

“Y-yes,” said Twilight, a tear in her eye. “Princess—” A small bead of pre pooled on the tip of Twilight’s cock, familiar pink and purple stars swirling in the goo.

“I want you to use this tonight,” said Celestia. “I want you to take a mare as your own and give her your foal.”

“But I—” Celestia squeezed her again. Twilight’s entire body felt like it was going to melt.

“No questions. I know that you have a foal of your own. But in accordance with our new traditions, it is time for you to give the kingdom another. As an alicorn, you must experience pregnancy as both stallion and mare. Two heirs are required.” Twilight had never heard of this tradition before, but she knew she was helpless to deny her. The purple alicorn brought both hands to her crotch as Celestia’s pulled away. She knew this cock wasn’t hers alone. Twilight whimpered as she touched her rod for the first time, feeling her teacher stroke sticky fingers through her flowing purple mane. “Who you choose is up to you. But you must choose somepony.” Celestia stroked her fingers up the bottom of her shaft. “Do you understand?”

“Yes, princess—” moaned Twilight, cringing into her teacher’s bust. The pleasure was incredible. She didn’t remember being able to grow a cock when she traveled through the mirror. She started rocking her hips, rubbing her soft purple hands up and down her length. It felt so hot! “Oh yes!”

At that moment, Celestia clapped her hand over the top of Twilight’s cock.

“Ah-ah-ah,” whispered Celestia, helping her hands from her shaft. Twilight felt the bed shift as the princess shuffled off her knees, then guided her student onto her back. As she fell, she saw Celestia’s glowing white bipedal form rise above her, her gold necklace dangling between two impossibly-large breasts. Next came her cock, its shape even larger than her own. A narrow stream of pre dribbled from the tip and across Twilight’s face. Then it pivoted down toward her lips as Celestia’s thighs straddled her head.

“I need you to do me first.” Celestia’s words tickled Twilight’s cock, which she then kissed. White hands again gripped Twilight’s shaft, and the student followed suit.

Twilight closed her eyes, then caressed her hands up the sticky flesh, guiding more and more of it between her lips, sampling Celestia’s delicious royal musk. Celestia’s mouth then descended down Twilight’s length, and as she was smothered by her royal weight, the purple alicorn knew exactly which mare to claim.

As she struggled to get comfortable on her improvised bed consisting of two ratty quilts strewn atop a half-dozen boxes of unused fireworks, Trixie was feeling less great and powerful than ever before. When a cool breeze whistled through the open window on the back of her carriage, Trixie sniffled as she shivered, her blue fur standing on end. Suddenly, she’d never felt so alone.
Trixie had returned to Ponyville the previous month upon hearing of a new form of magic, something that had swept through the town one hot weekend the previous fall. Donning a cloak, she first snuck into the town to see it with her own eyes.

In a park near the pristine town square, she zipped behind a tree as a pair of earth ponies approached. The chocolate-colored stallion was walking backwards, his blank flank on a collision course with a nearby bench. He was being pushed that direction by a cream-colored mare with a long light brown mane tied off in a single ponytail. She was kissing him, pushing him that way with her face. The mare then shoved the tiny stallion onto a park bench, causing his little propellor hat to fall from his head. He grabbed for it with short brown legs, but it fell to the grass.

“My hat!” said Button Mash in his nasally voice. Trixie was surprised how much bigger the mare was than the stallion. He was just a colt. Yet when Button’s Mom climbed onto the bench, straddling his tiny body, she shoved her face back into his for another kiss. Her long tail flicked up, revealing her cutie mark, a half-filled baby bottle with a pink heart next to it.

“Hold still, dear,” said the mare. “Mama’s sick. She needs her medicine.” Button Mash squirmed as she nibbled the tuft of fur on his chest. Her other hoof was between her hind legs, stirring her damp marehood.

“I think I’m sick too, Mom,” he said. “I feel—funny—” His gooey little pink cock began to poke its way out of its sheath. Small black hairs appeared on his upper lip. His mom giggled.

“You’re fine, sweetheart,” she said, kissing him once more. She sat on her hind legs and began to rub his cock with her hoof. Her son cringed. She giggled. “See? Doesn’t that feel good?”

“Unnnh! Mooom!” Button Mash shivered, then felt the tickle of a curved black mustache coil beneath his nose.

The more Button’s Mom rubbed, the more Trixie saw their bodies change. The two of them grew taller, their legs longer, and soon the mare’s hooves split into fingers that clutched one of the expanding breasts on her chest. The breasts were massive, full, the nipples as pink as her cutie mark. The tiny colt grew much faster, his body stretching the entire length of the bench, his tiny legs becoming powerful arms with dark rippling muscles. As Button Mash’s legs coiled between his mother’s thighs, his cock exploded in size, transformed into a rippling pink appendage. His mom tugged his massive cock her direction, then shoved it inside her marehood, which gushed as it stretched to grab him. The two of them moaned as their bodies collided.

“Unnnh! Oh, Button! Your joystick’s so hot!” cried his Mom. “Make love to me!”

Button’s Mom hopped on top of her powerful son, then collapsed on top of him, grinding her curves against his chest. The brown pony, whose hands had been grabbing the bench, now grabbed her instead, reaching around her to brush her glistening fur. The two kissed loudly, hungrily, and the bench continued to squeak to their lovemaking.

The groans grew louder and louder until, just a few seconds later, the brown pony’s body locked between her thighs, his flexing buttocks rocking side to side as he came deep inside her. As the two began to ease back into their old bodies, both of them gasping for breath, the tiny colt began to blush. His mustache was gone.

“Oh no,” said Button Mash, his mammoth cock flopping out of her pussy, still oozing with seed. “Did I do something wrong?” His mom giggled, easing a finger to his lips that slowly morphed back into a hoof.

“No, it’s okay, my dear,” she cooed, giving him a peck on the cheek. “It is your first time, after all. You’ll get better. Now, don’t tell Daddy, okay?” Button picked up his hat with his teeth, then flicked it on top of his head.

“Okay!”

Trixie was elated. She hadn’t transformed - she was too busy taking in the spectacle, but was glad that she had witnessed it herself. It was just as the rumors foretold - this was a magic even earth ponies could do. She had to find out the secret. She knew if she mastered this magic, she would become a household name - well, she would remain one - but this time for all the right reasons.

But Trixie soon found she didn’t know where to start. Just about every potential mate in Ponyville was taken, married or engaged by Celestia’s decree. She knew she couldn’t admit her ignorance, either - to do so just didn’t suit her. So she acquired the Alicorn Amulet with the hopes of using its powers to ensnare a partner who would transform her, too. As she fastened the item to her outfit, she couldn’t stop thinking about what she’d turn into when she was finally ready, if she’d become a creature even more beautiful than the two she had witnessed in Ponyville.

But the amulet’s corruptive energy was too strong, and it sidetracked her into a petty squabble with Twilight Sparkle. Though the blue unicorn had at least somewhat saved face after the incident, she didn’t dare show herself in that town again. What’s more, she had exhausted her nest egg in acquiring the amulet, and now found it even harder to find a village in Equestria that hadn’t heard of her infamy. And, worst of all, she was no closer to discovering how those two ponies turned into such beautiful creatures.

A tear rolled down Trixie’s snout. Nopony will ever share that magic with me now, she thought.

That’s when she heard a thump outside.

Trixie sat up, then heard a hoof knocking at her door.

“Who’s there?” squeaked Trixie. She remembered herself, cleared her throat, and returned to her stage voice. “Who dares awaken the Great and Powerfu—”

“It’s me, Trixie,” said Twilight flatly.

“Twilight!” Trixie gasped. The name carried more weight than ever before. With her rival now an alicorn princess, Trixie now feared her, felt even more unworthy of her presence. There was no time to comb her frazzled silver mane. As if on reflex, the blue unicorn jumped out of bed and bowed down facing her cart’s door, which slowly pushed open to reveal the hovering purple pony. Trixie felt a gust of wind, then heard the sound of four hooves against wood, and with the moon behind Twilight, she was now quite literally in the shadow of the purple pony. The door closed behind her. “What can I do for you, my princess?” Twilight walked up to her.

“Oh, Trixie,” said Twilight, brushing her mane with a hoof. The hoof slid gently underneath Trixie’s chin, guiding it upward. When the two mares met eyes, Trixie saw tears in Twilight’s eyes. “All I want is for you to be mine.” Twilight closed her eyes.

Trixie was about to say something when her words were stopped short by Twilight’s lips.

The kiss made Trixie’s whole body feel warm, but her fur stood on end like a chill. It felt good - really good. She tried to figure out why, to decipher the calculus of what she was feeling, but it continued to elude her. When Twilight’s tongue dipped inside her mouth, she tried to grasp that new sensation as well, but her mind felt clouded, slow, as if under a spell. A strange energy began to swirl around her marehood, which suddenly felt alive.

As Trixie’s own eyes closed, more of her body felt like it was no longer her own, her right-front hoof disregarding her visitor’s rank, choosing on its own to brush the fur on Twilight’s neck.

Twilight didn’t stop her. Instead, her purple hoof felt softer and softer against Trixie’s jaw, five shapes slipping up her cheeks and toward her throat. When Trixie opened her eyes, she saw that Twilight’s hoof had changed into something like she saw in the park. Trixie rocked her head to the right, breaking their kiss to rub her cheek against the soft fur of her palm. Twilight was still on all fours, but she looked bigger than before, and new shapes were beginning to sway from her chest. Her breasts.

“Twilight,” whimpered Trixie. “Can you - can you show me - how to change?” Twilight’s other hand slipped from beneath her legs, then reached between Trixie’s forelegs. As fur slid against fur, Twilight’s fingers nearing Trixie’s marehood, Twilight giggled. She brought her face to Trixie’s right ear.

“Of course,” Twilight whispered. At that moment, one of Twilight’s fingers touched something at the tip of her marehood. Trixie moaned, her whole body trembling as she straddled Twilight’s long purple arm. Something spat out of her, something warm that began oozing down the insides of her thighs. She felt embarrassed, but it felt so good that she urged it to continue.

When one of Twilight’s fingers slipped inside of her, Trixie moaned even louder. Her hoof on Twilight’s neck flexed, and suddenly she could feel fur between new fingers. Trixie peered over Twilight’s shoulder and lifted her hoof - her hand - to the moonlight, watching in earnest as her leg narrowed into an arm.

“I’m changing–unh!” gasped Trixie, feeling Twilight’s fingers continue to root inside her soaking snatch. “I’m—”

Suddenly, Twilight’s arm tightened, then hoisted her up. Trixie stumbled on two changing legs, then fell flat on her back across her bed, causing the boxes beneath to squawk. Twilight remained on all fours, crawling up the foot of her bed. She caressed Trixie’s flanks, welcoming her lengthening legs as they slid by either side of her head and over her soft purple shoulders. Deep in Trixie’s light blue valley, Twilight kissed, then licked a spot on her inner thigh, and Trixie’s torso lengthened, coiling her growing body into the far end of the carriage. Trixie reached one hand down her new height to Twilight’s mane, feeling the purple pony’s face sink lower, kissing one thigh, then the other as it did.

Trixie squeaked when Twilight’s lips smashed into her marehood, and as the blue pony pressed her hand even harder against the back of Twilight’s head, two large breasts thrust quickly from Trixie’s chest, squishing around her arms. She licked her lips and gazed down at one of the shapes, which she now cupped in one of her hands, and the dark blue nipples that protruded from each.

“Unh!” Trixie cried, her buttocks shuffling forward on the quilts as Twilight drank her. The sensation caused her fingers to pinch the fleshy nub atop her right breast. She felt pain, but then still more pleasure, and with it the approach of an incredible climax. Panting deeply, still playing with Twilight’s beautiful mane, Trixie continued to caress her new body, watching Twilight’s beautiful wings flutter behind her. “Oh Twilight—my princess—my Twilight!”

Just before anything more could happen, Twilight leapt up on her hind legs. The movement startled Trixie, but not as much as what she saw. A giant purple cock, much bigger than Button Mash’s, now thrust directly at her. Though suspended a couple feet above her loins, she could feel its heat, and in the shadows, its wet glutted flesh still twinkled. Twilight grasped the shape, then got back to her knees, helping Trixie move her legs even further apart. Knowing her mare was close, Twilight gave Trixie’s marehood just one swipe with the tip, then rammed the whole thing in.

Trixie never felt so filled with anything as when Twilight stuffed her oozing blue snatch. She moaned on the edge of a scream as Twilight fell on top of her, mashing their breasts together, erect nipples tickling each other. Twilight eased out, but hammered inside her just as hard, and Trixie found herself speeding toward orgasm even faster than before. Trixie’s hands reached behind Twilight, trying to pull her closer still, feeling her juices flow over the invading shaft that threatened to turn her marehood inside-out. Faster and faster, the two former rivals fucked as lovers, their motions blurred into something both were helpless to stop. Louder and louder the carriage creaked, upsetting books and trinkets that thumped onto the floor around them.

They came together.

Hard, deep, pounding thrums unleashed thick ropes of Twilight’s speckled spunk as Trixie’s cunt wrenched his length, yanking the seed deeper and deeper into her changed womb. They quivered and quaked as one, their hands fumbling over each other’s bodies, trying to hold onto something. Twilight’s hands grabbed Trixie’s hair, and she screamed as she squeezed Twilight’s buttocks, keeping her buried to the hilt in between her quaking lips.

As their bodies slowly reverted, Twilight still on top, the two slowly caught their breath. Twilight’s cock reverted back into a soaking clit, her glittering cream still splattered over both their loins. Trixie had no idea how much she’d grown in the change until she noticed how much bigger the carriage felt all of a sudden. But the two never stopped staring at each other, their eyes twinkling, their bodies blushing, fur cloaked with sweat and the unmistakable scent of goddess sex.

“My princess,” whispered Trixie, guiding one of Twilight’s hooves to her lips. She kissed it, then traced her tongue around the edge. The hoof began to flatten once more, fingers stretching from its shape. Twilight brought her other changing hand to Trixie’s face and eased forward, letting her long purple and pink mane brush Trixie’s cheek.

“No. My princess,” said Twilight. Trixie felt a buzz over her clit, Twilight’s magic teasing her dripping marehood from bottom to top. Trixie tried to concentrate, but could do little more than tickle the princess’ growing cock. It was enough. Twilight giggled to her faint blue caress, feeling her shaft expand even faster, her breasts returning with Trixie’s. At last, the two had found each other as never before.

Trixie had discovered the secret.

Twilight would have a second spouse.

And both would have a foal of their own.