Ambrosial Excretions

“I-I’ll see you at the banquet,” Twilight waved goodbye to her friends as they walked off, and sighed in relief, turning to Spike to whisper. “Come on Spike, let’s find a room to change before the banquet.”

“We can’t!” Spike whispered again, shaking his head and pointing at the pamphlet Celestia had given them. “Those things are expensive and difficult to make, they already have ponies working overtime and they don’t even know what they’re making! Sorry Twi… but we gotta wait until it’s fully full.”

And so she found herself waddling her way to the banquet table, even if consuming food in an already dirty diaper seemed one of the most counter-productive things one could do. She cringed as she lifted her dress and turned her sagging hindquarters towards her designated seat, already knowing that it wouldn’t be a comfortable feeling.

It was worse than she expected. She felt the pressure spread out her load, mixing it with the urine into a slimy mess between her thighs and around her hips, her plot cheeks imprinting into the mess to rest against her seat.

Worse, despite being very uncomfortable, it was also more pleasurable than she’d like, more of the goo pressing against her marehood, feeling as hot as she’d imagine a penis might feel against her, not that she knew to compare. She looked down at her plate, then over at some tasty looking broccoli salad. She smiled just slightly, lighting up her horn with the intent to life some over to her.

“Hold it!” Spike stood in the chair next to her, thumping her horn and turning off the levitation.

“...Spike?” Twilight tensed her face up, not looking directly at him for fear that she’d look too mean in her current mood. “What is the matter?”

“It said you have to be careful about your diet,” Spike said. “To maximize the effectiveness of your um… ambrosia.” It was nice of him to phrase it in a non-obvious way in public at least.

“I see,” Twilight took another deep breath in and out like Cadance had showed her. “And what should I eat?”

“Cake, mostly,” Spke said. “But anything sweet in general… also hay burgers, but I don’t think there are any of those here. Hey, I wouldn’t complain about this part if I were you!”

Well that explained a few things about the legendary royal cake-craving. She had always though it was a little odd when she saw Celestia shoving cake down her throat like an addict. Twilight nodded slowly, using her horn again to cut a giant cake that looked far too sweet for her enjoyment, taking a full quarter of it and placing it on her plate.

“Taking after Celestia a little there, are you darling?” Rarity smiled from across the table. “Alicornification giving you a sweet tooth?”

“There’s nothing wrong with a sweet tooth!” Pinkie giggled happily as she shoved her quarter of the cake into her mouth all at once.

“I-I guess,” Twilight smiled at them, letting it be a joke if that would cover up the real reason. She started taking bites of her piece much slower.

She talked with the others, but several times she realized she’d started to rotate her hips against the chair, subconsciously wanting to jar the mess around a bit to rub the warmth between her cheeks and against her slit. She stiffened her hips each time to stop. It wasn’t just the squish or the warmth; the magical nature had started to tingle against her, a soft electrical charge buzzing up through her like a vibrator. It reached a point where staying perfectly still wasn’t enough even.

Eventually it became too much to bear. Her marehood was burning as if she was in heat, and she doubted the medication that mares normally take to stifle that would work on her now. She allowed the conversation to drift away from her, eating the cake with her magic slowly.

Once everypony wasn’t paying as much attention, she took another deep breath and very slowly moved her right hoof off the table and into her lap. Biting her lip slightly, she testingly pushed it against the fabric, feeling slightly less crinkly than before, sliding it up and down and shivering a bit at the resulting feeling bubbling up through her. If she could just discreetly rub one out… the rest of the evening would be a lot easier…

But suddenly she felt her hoof tugged back up onto the table and put it where it had been. She blushed more intensely than ever when she realized it was Cadance’s telekinesis and that the princess had spotted her stealth masturbation. Cadance motioned her head politely to Celestia, who turned to look at Twilight. They both smiled gently at her, but Twilight felt like a foal about to get grounded.

“I know it tingles, dear,” Celestia whispered to her. “But we still have to maintain royal decorum and keep your hooves over the table. If you feel need, please order a servant or guard to discreetly move beneath the table to sate you.”

Twilight’s eyes widened slowly the more Celestia spoke. Then went twice as large when Spike, on her other side, saluted at Celestia after over-hearing with his better dragon ears.

“W-we can wait, Spike!” Twilight whispered and shook her head.

“Actually, we can’t,” Spike pointed at the pamphlet again. “If you get too pent up, the unit could blow right off you and cause a chemical disaster.”

“Celestia’s eldritch mane…” Twilight swore. This was getting as absurd as it was humiliating.

“I’m gonna um… go potty,” Spike announced all too loudly, hopping off his seat and walking away from the table.

Twilight watched out of the corner of her eye as he looped around stealthily and crawled under the table at the far end. A few minutes later, he heard him quietly apologizing to someone as he passed Luna, as if there was another servant under there he needed to pass. She finally felt his small claw tap her leg.

She couldn’t have been stiffer as she slowly parted her hind legs as wide as she could, but she really needed this. If not for herself, then to prevent a potential tragedy. At least thinking about it that way lessened the guilt aspect a little. Maybe it wouldn’t be too bad. Spike was good at full-body claw massages, even if he’d always politely avoided certain areas before.

Given their sibling-like relationship, feeling Spike’s claws crinkle against the front of her diaper felt as shameful as it would if Shining did this. She strained to take another bite of her cake, fork shaking violently in her magic, trying not to hyperventilate as her whole body burned.

Spike moved his claws easily to where her marehood was; he was plenty familiar with its location since he was usually eye-level with it at his height. He kept his claws in to keep from tearing the fabric, but pushed his thumbs firmly against her slit as his other fingers rubbed circles around either side.

That seemed to barely get through through the thick material, only making her whimper in frustration more. He paused as if thoughtful for a moment, then pressed both hands firmly against her, digging his claw in just enough to catch the material and move it with his claws. He then flexed his legs, pushing himself up and down slowly to rub the inner material against her.

She heard a little ‘ugh’ from him at the smell from shifting it around and feeling the squishiness beneath the diaper. While thankful he wasn’t creepily enjoying it, it made her more self-conscious to know what an unpleasant task it was.

Twilight found difficulty thinking about that though when the material started to move more. As impossible as it seemed, the spongy interior seemed softer the more disgusting it was, and she couldn’t stop shivering when he began to work it up and down over her marehood. She tried not to bite her lip as she chewed her cake.

The pressure moved upwards slightly, pressing against her breasts up on her tummy, moving the pliable mounds up and down as well. She felt her nipples harden enthusiastically against the fabric as she began to undulate her hips slowly against Spike’s dutiful affections. The magically resistant material had kept the heat in perfectly, and the semi-liquid sloshing against her still felt as warm as when it left her body.

She put down her fork and concentrated hard on not seeming agitated, but it wasn’t easy. As conservative as she could be, Twilight usually got a bit loud during her private masturbation, so it was difficult not to verbalize the pleasure now swelling up from her thighs and up through her body. Luckily the other princesses seemed to get the idea, and Cadance had started a rather loud debate with Pinkie about whether something could be too pink.

Twilight gripped the table, trying not to shift it too much with the motions. She raised her hips slightly off the seat for freer movements, and began humping against Spike’s braced fists in earnest. She hated to admit it, but getting discretely masturbated through a messy diaper in public was turning out to be the most erotic thing she’d ever experienced.

When she went over the edge, her nethers shivered and convulsed enough that it sent ripples through her diaper. Another burst of fluid joined the rest and splattered into covering, and she strained not to knock her chair over with her shaky movements. Unfortunately, the surprisingly intense orgasm also made her finally cry out, bellowing out a squeal of a moan as she gripped the table hard.

A moment later, Spike had stopped and everypony was looking at her with wide eyes, save for the other princesses that were looking about a bit nervously. Twilight cleared her throat, sitting herself back in her seat and stammering an excuse, “Ah um… bit my tongue. Sorry.”