Futanitiation

Twilight Sparkle, Equestria's newest princess, settled into her bedroom at Canterlot Castle as Princess Luna's moon rose into the sky. Given the events of the past 24 hours, from her surprise transformation to her coronation the following morning and multiple events throughout the capital city, the young pony was quite tired. She had been told to stay in Canterlot that night while her friends and family went back home. She didn't know exactly why she was told to do so, but she loved Canterlot very much, as it was the city she grew up in.

The purple unicorn-turned-alicorn levitated her new crown off her head and placed it on the bedside table before climbing into the massive queen-sized bed before her. It was covered with a thick, purple comforter with white sheets underneath. She pulled the covers over herself and lay back, eager to feel her body relax on the soft mattress. Unfortunately, her new wings were the first to touch the white sheets, and she quickly remembered that she was going to have to sleep in a different position. This was a problem she had had the previous night on the train when she and her friends came to Canterlot for the ceremony. "Ugh..." Twilight groaned to herself as she sat up. She spread her wings in an attempt to be able to lie on her back, but when she tried, it didn't work. It was putting too much stress on her new joints.

Twilight eventually resorted to laying on her stomach. She had never slept like this at home, and she wasn't sure it would be comfortable. Thankfully, she was able to relax into her bed and didn't have to worry about anything pressing against her wings. She levitated the covers over her body once again and turned her head sideways, resting it on one of the white, fluffy pillows. The blanket and comforter only put light pressure on her wings, but she could easily handle it, as the main sensation travelling through her body was the warmth that circulated under the covers, slowly making her eyes close more and more until she was finally asleep.

Twilight awoke to the sound of somepony knocking on her door. She stirred slightly, annoyed that what was a decent sleep had been interrupted. She sat up and looked across the darkened room, trying to find the clock on the wall. The alicorn lit her horn, which illuminated the majority of the room around her. She soon found the clock, but became very displeased once she saw what time it was. "It's midnight..." she groaned, getting out of her bed, "Who could want something this late?"

The purple mare stood in front of the door and opened it with her magic, looking out into the night. There was nopony at her doorstep, which annoyed her even further, but she noticed a note on the ground in front of her, and it had her name written in some familiar writing. She quickly unfolded the note and read it to herself. It said:

Dear Princess Twilight Sparkle,

You are needed in the room on the castle's lowest level immediately. Please do not delay. This is a very important matter.

Signed,

Princess Celestia

A small amount of adrenaline ran through the young princess as she realized that she could not wait until morning to tend to this new matter at hoof. Assuming this was serious royal business, she turned back to her bedside table and took her crown in her magic, placing it back on her head before closing the door and racing down the spiral staircase, wondering what her former mentor had in store for her.

After careful navigation of multiple hallways, Twilight eventually found the curved staircase within the castle that she needed to descend. It was dark, the walls and stairs an eerie mix of gray and black that seemed like a staircase leading to a dungeon. Gulping, the princess started trotting down the steps, not being able to see what was at the bottom. Every twenty or so steps, the amount of light that surrounded her slowly faded away, making her that much more nervous. She had never visited this part of the castle, as she had assumed it was a secret dungeon that she didn't need to know about.

Slowly but surely, Twilight climbed down the 400 steps until she reached the large, steel double doors that rested in-between two flaming lamps on the wall. "This must be it..." Twilight thought to herself. She had no idea what was going to happen when those doors opened. Was she going to be punished for something she didn't know she did? Was she going to be dethroned in secret? She could only speculate until it happened.

Twilight nervously knocked on the door, the sound echoing up the staircase in a very creepy fashion. Once it faded, Twilight could hear nothing from behind the doors, so she reached her hoof up to knock again, but she stopped when a small hole in the door opened, and she could briefly see a pair of eyes looking down at her before the hole was closed shut, and then she heard a couple of hefty locks being undone. Finally, the two large doors opened, a cloud of dust forming around them as the decently lit room shone its light before her. When the dust subsided, Twilight could instantly make out who was in front of her.

"Hello, Princess Twilight," came the voice of Princess Celestia. It was low and husky, something Twilight had never heard from her former teacher. "Please come inside. We have some important business to take care of."

"What's this all about?" Twilight asked as she entered the room.

"You need not worry, Twilight," Celestia said, closing the double doors behind Twilight, "You are not in any trouble, if that's what you're thinking. You are here for your official initiation."

"Huh? Didn't that happen this morning?"

"That is what everypony thinks, Twilight," came another voice which Twilight quickly made out to be that of Princess Luna, "But to officially be recognized as a princess of Equestria, you must go through a process which we will be performing on you now. It is a tradition that we princesses have all partaken in."

"Wh-what is it?" Twilight asked, nervously.

"It's very simple," Celestia replied, "You will have to grow one of these." The white alicorn then turned to her side and made a certain part of her underside visible to her former student.

Twilight couldn't believe what she was looking at. In-between Celestia's hind legs was a fully erect and anatomically correct stallionhood, complete with a pair of lemon-sized testicles. True, she had seen stallions in a horny state before, but the fact that there was a full set of male genitalia on a female, especially Princess Celestia, caused her brain to go haywire. The mere sight of it almost made the purple alicorn vomit, but she was able to hold it in. "Wait...you've...all gone through this?" she asked Celestia.

The immediate response, however, came from Luna. "Of course," she said, prompting Twilight to turn around and face her, "Like I said, it is a tradition that we intend to keep alive." It was at that moment that Twilight saw the biggest, blackest horse dick she had ever seen in her life, along with a set of nuts the size of Celestia's. Now she was looking at not one, but two mares with male body parts. Nothing science-related in Twilight's brain could make sense of the situation. How was this possible?

"Hold on," Twilight spoke, "What about Cadance?"

"Oh, I'm here, too. Don't worry," Cadance replied, coming into Twilight's view. Like the other two alicorns, Cadance had her own fully erect member and hefty balls on display for all to see.

One of Twilight's eyes began to twitch. How could she not have known that this was coming? She had never seen any of the other princesses with these body parts before. At this point, Twilight had been officially mind-fucked. "S-So..." Twilight began again, "I-I have to get...o-one of those?" she finished while pointing to Cadance's stallionhood.

"That is correct, Twilight," Celestia responded.

"B-But how? You're going to use magic, right?"

"Well, sort of. You see..." Cadance said, "We're going to fill all of your...holes...with our...seed. It's laden with magic that will make you grow these extra body parts," she finished with a blush, feeling a bit awkward having to say something so erotic to her sister-in-law. Twilight herself was completely motionless. Cadance's blush faded as she spoke up again. "But, once you're all done with it, it's really not that bad. Celestia had to do the same thing with me when I became a princess. At first, I thought it was really weird, but now, I'm totally used to it. It's actually kind of a fun thing to have. It's like a little secret that we princesses share, since barely anypony else knows we have them."

Twilight remained frozen in place. Her eyes were wide, her heart was beating rapidly, and it almost looked as if she wasn't breathing. This is what she had to wake up in the middle of the night for? THIS? A secret second transformation? She didn't know what to think. Her common sense was telling her that this was completely unnecessary and downright lewd, but at the same time, the scientific part of her brain made her curious. She had only read about equine anatomy in school, but she had never experimented with it in real life. Now, she was being told that she would grow a set of male genitalia all her own. She would be able to perform countless experiments with it, pleasuring herself and studying what happened. True, she had pleasured herself multiple times, but the thought of feeling pleasure from a long, thick cock gradually made her wet with desire.

"Aside from the enjoyment aspect, Cadance," Celestia said, "Going through this process makes you one of the most unique ponies around."

"But..." Twilight said, "Doesn't being alicorns make us unique? There's only four of us."

"That's what she thinks..." Celestia thought to herself.

"It does," Luna replied, "But this makes us...more unique," she finished with a sly smile.

Now becoming more curious than ever as to what it would feel like to have a stallionhood, Twilight, whose arousal had begun to form a tiny puddle under her rump, asked, "So...what do we do first?"

"I suppose it would be optimal if we did everything at once," Celestia replied, "But I think it would put us in a rather uncomfortable position."

"Perhaps Cadance can lead the way," Luna said to Twilight, "Then my sister and I can do our part at the same time."

Twilight immediately grew nervous at the mere prospect of what Luna had just suggested. She had never had intercourse before, and now her first time would involve double penetration. Still, her curiosity and arousal were doing a decent job of steering her away from those thoughts. "Ummm...yeah. I think I'd be okay with that," Twilight responded.

"Great!" Cadance replied, "Let's get started."

Twilight sat down in front of her sister-in-law, her eyes fixed on the dark pink phallus that was connected to her underside. She paused, then looked back at Celestia. "I have a question," the purple mare said, "Will I still have, you know...my other parts after this?"

"Absolutely," Celestia replied, turning around to show her that she still had her own marehood above her hefty ballsack.

"Okay," Twilight said, turning back to her sister-in-law. "Cadance," she asked, "Is Shining Armor okay with this?"

"Oh, of course," Cadance replied, "He's one of few who know our secret outside of ourselves, and he knows that royal business always comes first."

"Good," Twilight responded, "So, which part of me are you...well, going to put that into?"

"It would be best if we start with your mouth." Twilight's eyes widened slightly, becoming the slightest bit nervous that she was going to be putting that in her mouth.

Twilight eventually agreed, and she scooted forward until the tip was mere inches from her muzzle. She took a few sniffs, the musk coming from the pink alicorn not being as pungent as she thought it would be. It actually made her relax. Twilight leaned her head forward, the tip of her muzzle making contact with the tip of Cadance's cock. "Am I going to be able to fit this in my mouth?" she thought to herself. She told herself that she wouldn't know until she tried, so she stuck her tongue out and started to slowly lap at the tip, the action sending a shiver through its bearer.

Twilight soon opened her mouth all the way and began to encase the tip in it. The tip itself was the widest part of the cock, and Twilight was able to fit it all the way into her muzzle, sending more pleasured shivers through her sister-in-law.

Wait. Hang on. This was Cadance. Her sister-in-law. Her old foalsitter. One of her best friends. For some reason, a long flash of memories came into Twilight's mind. She thought of all the amazing times she and Cadance had throughout the years, and now was beginning to realize just how much she loved and appreciated her. Now was the perfect time to express those feelings through actions.

Twilight moved her head forward, slowly beginning to bob up and down on Cadance's cock. With each movement, she could hear moan after moan coming from above her. "Ahhh!" Cadance cried out, "Twilight! Yes! That's perfect! Keep going! Ahhh!" Twilight did as she was told, not ceasing her ministrations in the slightest as she began to use her tongue and hooves to pleasure Cadance that much more. She could already taste the pre-cum leaking from her tip, the surprisingly sweet taste pushing her on, hoping to receive more of it as she continued blowing the pink alicorn.

Twilight's hooves started moving up and down faster and faster, her head not moving as it held just a little more than the tip inside it. She could feel the veins throbbing madly as Cadance's heart rate increased, Cadance herself panting heavily as sweat began rolling down her forehead.

The pink mare's eyes were halfway open, and she began to feel a familiar pressure start to build as the alicorn below her pleasured her. "T-Twilight!" Cadance cried out again, "Ahhh! I'm close!" She instinctively grabbed Twilight's head and held it in place, not wanting the sensations to end.

Twilight herself was a bit taken aback by Cadance's actions, so she looked up at her. Cadance looked down and said, "Ahhh...make sure you swallow it all, Twilight. Otherwise this whole thing won't work." Twilight nodded, immediately going back to pleasuring her sister-in-law and preparing herself for what was to come.

The pressure continued to build inside Cadance's loins until she could hold it no longer. With a primordial scream, she threw her head back and let herself go, her white, hot seed shooting out of her stallionhood and into Twilight's mouth, all while she orgasmed out of her marehood, as well.

Twilight was unprepared for what shot out of Cadance's tip, the first long, thick rope hitting the back of her throat almost instantly. She miraculously swallowed it without choking, and not a moment too soon, as the next one prevented her from drawing in a much-needed breath. As Cadance rode out her orgasm, Twilight did as she had previously been told to do, swallowing every last drop of cum that shot out of Cadance's member. To her surprise, just like the pre-cum, the actual seed was really sweet, almost like raw, liquefied sugar. She hummed as she savored the wonderful taste.

Soon, Cadance ceased cumming inside Twilight's mouth, and Twilight herself gave one last suck and held it, pulling her head back as she drew the last of the cum out of her sister-in-law. She eventually detached, but not before sticking the tip of her tongue into the small opening at the end of the penis, making sure she got every last bit of cum, as if she was triple-checking all of her already double-checked checklists back home.

Twilight finally swallowed the last of Cadance's cream, sighing as she lay backwards, relishing in its warmth. Unfortunately, her cozy state was interrupted by Celestia, who quickly stood over her. "Well done, Twilight," she said, "Now Luna and I must get started filling the rest of you up."

Twilight had almost forgotten that she was going to be rutted from both of her rear holes. She looked up at Celestia, a worried look on her face. "I-I've never had sex before," she said, quietly, "I was hoping my first time would be with a stallion."

"Do not fret, Twilight," Luna said, reassuringly, "We will be as gentle as we can. Plus, you will not feel any pain."

Twilight looked puzzled. "How?"

"Let me explain that," Celestia said, "When I performed this on Cadance, she was a virgin herself, but she did not feel any pain. I, like her with you, started with her mouth, and the seed acted as sort of a local anesthetic for what came next."

"Interesting..." Twilight replied.

"I believe it is time we get started, sister," Luna said, "Don't you think?"

"I agree, Luna," Celestia replied. The white alicorn then looked down at her former student. "Twilight, please stand up. There is something I need to do for preparation purposes." Twilight did as she was told, and Celestia quickly noticed that the new princess had been getting quite turned on from what she had just done with Cadance. "And I believe you have provided me with the most ideal way to do it."

Twilight once again looked puzzled, but brushed it off as soon as Celestia stood over her once again. Twilight could feel the large tip of Celestia's stallionhood press up against her labia, and, without warning, she felt it enter her. "AHHH!!!" Twilight shrieked. She hadn't expected her former mentor to proceed so quickly, but she couldn't help but feel an immense amount of pleasure from being spread wide. All of a sudden, Twilight could feel a tearing sensation inside her, and she knew exactly what it was, but once it finished, she was surprised to find that she felt no pain. "Celestia was right," she thought to herself. Cadance's semen had somehow numbed her in the precise areas where she would feel pain at this moment, and all she felt was pure, raw pleasure.

Unfortunately, that pleasure was short-lived as Celestia pulled out of her completely, the white alicorn's member already coated thoroughly in Twilight's juices. "Please hold still, Twilight," Celestia said, prodding her former student again. This time, however, she aimed for the other hole, and Twilight gasped upon feeling Celestia poking at her tailhole. She was nervous, and because of that, her anus was clenched tight, not wanting to accept the large cock that threatened to stretch it beyond its limits.

All of a sudden, Twilight felt a new tingling sensation throughout her body. She felt herself relax, and at the same time, she became more aroused. She had to assume at this point that Cadance's seed was not only acting as a local anesthetic, but also as an aphrodisiac.

Celestia quickly noticed Twilight becoming more relaxed and pressed forward, trying to press the head of her erection into Twilight's anus. Thanks to the lubrication, she was able to slip the head inside with ease. Twilight moaned at the completely alien sensation, her butthole immediately clenching down on the intruder, despite the relaxed state she had been in earlier.

Soon, Twilight relaxed again and Celestia kept pushing herself inside. About twenty seconds later, Celestia had pushed her cock completely inside her former student's rear, reaching depths that Twilight didn't even realize were there. "Ooooohhhhhh!!!..." Twilight moaned, feeling more filled than she'd ever been in her life.

Not even a second later, Celestia wrapped her forelegs around Twilight and sat down, both of them still connected as she and Twilight sat upright. During the movement, Twilight's new crown slipped off her head and started falling to the ground, but before it could, Princess Luna grasped it in her magic. She then brought forth a small pillow from a corner of the room and placed the golden tiara on it and set aside. She then walked in front of Twilight and Celestia, her large member still fully erect as she sat down in front of them.

Luna placed her forehooves on Twilight's shoulders, lining her cock up with Twilight's 'main' entrance as she looked her in the eyes. "Are you ready?" she asked.

Twilight glanced up at Celestia's face, then back at Luna. "Mmhmm," she mumbled.

Taking the initiative, Luna pushed forward, spreading Twilight's now slightly loose cunt as her massive member became enveloped in the younger alicorn's warmth. Soon, she was all the way in, the tip resting dangerously close to Twilight's womb as the Princess of the Night wrapped her hind legs around Twilight's and Celestia's hips.

Twilight was now sandwiched between the two royal sisters, their cocks deep inside both of her lower holes. She looked up at both of them, and they smiled down at her. At that moment, Twilight began to remember all the time she had spent with Celestia when she was still her student. She had become a second mother to the young mare, and she loved her very much, but she never could have imagined loving her this much. Being this close to her former mentor gave Twilight a feeling of indescribable joy and pleasure as she leaned up against Celestia's soft, white chest. At the same time, Twilight couldn't help but develop further affection for Luna, as well. Though she hadn't known her as long as she'd known Celestia, she had turned her life around drastically, teaching her the importance of friendship. Ever since then, the two had been seeing each other more and more often, and they always enjoyed it immensely.

As Celestia and Luna surrounded Twilight with their massive wings, they each started to slowly move inside the young princess. Luna pushed in first, her tip poking against Twilight's womb, making the purple mare scream in absolute bliss. As Luna pulled back, Celestia pushed upward, sinking her member deeper and deeper into Twilight's rear. The two of them alternated these motions as Twilight moaned and cried out in pleasure.

There were no words to explain how Twilight was feeling. She had never been this close to Celestia and Luna, and now that she was, combined with the fact that she had just blown her sister-in-law, she couldn't help but feel that this would be a night that she would remember forever and would always cherish.

Overcome with affection for the royal sisters, Twilight leaned forward and caught Luna off guard by pressing her lips to hers. Luna quickly took the initiative and pressed her lips back against Twilight's, turning her head at an angle to allow the highly-anticipated tongue play. A few seconds later, Twilight stuck her tongue out, poking against Luna's lips. The midnight blue alicorn obliged, parting her lips to allow her and Twilight's tongues to meet. Both mares moaned into each other's mouths as their bodies were racked with intense pleasure.

Twilight soon pulled away, a trail of saliva hanging between her lips and Luna's. As it fell away, Twilight tilted her head upward and looked at Celestia, hoping that she'd notice her. Forunately, she did, and she immediately kissed Twilight's waiting lips, not waiting even one second before sliding her tongue into her former student's mouth. Every time she pressed her lips further against Twilight's, Celestia would give a very deep thrust into the purple alicorn's rear, making the mare moan loudly into her mouth.

Soon, everything became too much for Twilight. The feeling of two stallionhoods penetrating her at the same time caused the heat in her loins to grow seemingly exponentially. "Ahhh!" she exclaimed, her voice laden with pure lust and pleasure, "I-I'm gonna cum!"

At that moment, Twilight felt another new sensation hit her. She looked down and noticed another hoof rubbing her swollen clitoris, and then she realized who that hoof belonged to. "Now, Twilight," Cadance whispered seductively into her sister-in-law's ear as she applied more pressure to the purple mare's love button, "Cum right now. Let it all out."

Twilight screamed in pleasure as she felt more and more pressure throughout her body. Then, all of a sudden, she felt Cadance press her lips to hers, immediately shoving her tongue into her sister-in-law's mouth. That was it. Twilight's ticking time bomb of a pussy exploded, clenching madly around Luna's stallionhood and letting loose a copious amount of marecum, coating Luna's cock and scrotum in her fluids.

At the same time, both royal sisters moaned in unison as both of Twilight's holes clenched tightly around them, tipping them both over the edge. Simultaneously, they released their massive loads into Twilight's vagina and asshole, filling them in an instant. Twilight moaned audibly as she felt the hot, sticky fluid enter her passages, the heat nearly causing her to go unconscious. Thankfully, she never did, and she was able to experience every little pleasure-laden moment as Celestia and Luna filled her to the absolute brim.

After a while, the orgasms of both the royal sisters ended, and they magically levitated Twilight off of them and set her on a nearby mattress. Twilight could only bask in the warmth of the princess' seed for a short time before she felt yet another tingling sensation sweep over her body, primarily in her nether regions. She sat up and looked down, watching her clitoris painlessly split into two before the new upper half started growing. It got longer and longer, wider and wider, and Twilight could feel two unfamiliar sphere-like objects form inside her and descend down into a new, fleshy sack that hung just below her marehood, both parts clearly visible. Soon, what was once Twilight's second clit had finished growing, and what was left was a long, thick, dark purple cock with a ball sack of the same color hanging behind it.

"It appears that the seed has done its job, Princess Twilight," Luna said, happy to see that her sister's former student now had the same body parts as the rest of them.

"Wow..." Twilight said, looking at her new appendage, "It's...interesting. So, does this mean you officially recognize me as a princess now?"

"That is correct, Princess Twilight Sparkle," Celestia replied. Twilight smiled, happy that the process was over and done with and that she was officially a princess to the other three mares in the room.

Twilight then yawned. She then looked up at Celestia and asked, "May I go back to bed now? It's been a long day."

Celestia, along with Luna and Cadance, gave Twilight a devilish smirk. "Oh no," the white alicorn responded, "We're not quite finished yet..."