Portalbelt XXX

Twilight had that look in her eyes — the look that left Rarity nervexcited, terroraroused, hornyscared — turned on, yet decidedly apprehensive. It was the look that said Twilight was planning another of “those” experiments, the ones Rarity suspected that Twilight secretly enjoyed the most, the ones for which Twilight increasingly seemed to favour Rarity as a “test subject”.

That wasn't to say Twilight had become less interested in exploring the magic of sexuality with her friends — of whom she now had many in Ponyville — but Rarity was one of the five Twilight was closest to, and most likely to share new experiences with.

Like the time she'd nervously revealed to them all that she had "male" sex organs, along with her marehood. Things had progressed much more swiftly after that. Learning that she wasn't alone in this, that Applejack was also a “pony of both parts”, had been a comfort that really brought Twilight out of her shell.

No, Rarity suspected this bias was more an alignment of taste. Twilight, it seemed, rather enjoyed tying somepony up, or strapping them down, or locking them in, as the case may be. She enjoyed designing and demonstrating devious devices to dominate and degrade. With such creativity for contriving sexual torture, Rarity at least half-suspected Twilight would one day invent and entirely new fetish, if she hadn't already.

But Twilight was a good pony, who would never intentionally harm anyone (without good cause). She needed a suitable submissive subject, somepony who enjoyed being reduced to a mere sexual plaything and thoroughly used, both by Twilight and by anypony else who joined the “experiment”.

Rarity gave a small embarrassed chuckle as she contemplated her train of thought, and how she couldn't deny her eagerness to be Twilight's favoured test subject.

“Hi Rarity!” said Twilight, radiating forced casualness. She had entered the boutique late on Friday afternoon, when Rarity was just preparing to pack up. “Are… you busy this evening?”

…

An hour later, the boutique was closed, Rarity had cleaned herself — outside and inside — in preparation, and Twilight had set up some… apparatus, on the table in Rarity's living room. The blinds were pulled shut.

“So, uh…” Rarity began, looking around the room, “will it be just the two of us tonight?”

Twilight smiled. “Oh, well, I was planning to involve some other participants, if that's alright. But they won't be here, exactly.”

Rarity frowned in slight puzzlement at this, but then she rather enjoyed being surprised by Twilight's creativity, so she only nodded and murmured assent.

Twilight coughed, and her face shifted to a more business-like expression. “Now then. There will be no safeword for this experiment, instead you need only leave the couch to end things early.” She gestured to the furniture in question. “Of course you will not be restrained from leaving in any way. Is that acceptable?”

“Yes darling,” Rarity nodded, making her way over to the couch. No safeword, she thought, most likely meant that her mouth would otherwise be occupied. That was good to know.

“Before we begin,” continued Twilight, “I need you to put this on.” She levitated a package from her saddlebags. “I'll help you ensure that it's in place properly, but it will be easier if you take the lead.

Opening the package, Rarity glanced at the attached documents, the words “Portal Belt” immediately conjuring up some ideas. The device indeed resembled a chastity belt of sorts, with moulded cups for her teats and a pair of flat-ish boxes positioned to cover her private areas. The rear strap included a dock ring, and the boxes were emblazoned with circular logos.

Ah yes. What was the name of that company again? Atomicky scientists? Something beginning with “A”. Twilight had been talking about them quite a bit lately. Quite an… esoteric lot, from the sounds of it.

The belt seemed quite well made. The straps were adjustable, the entire inside lined with a soft rubbery grip. Twilight gripped Rarity's tail and spread her buttcheeks while securing the harness over her hips, ensuring that the whole contraption wouldn't budge even slightly.

Once both ponies were satisfied that the belt was in place, Rarity climbed onto the couch. She couldn't quite sit normally with her dock lifted by the belt, so instead she leaned back to a more reclined position, legs spread apart.

Twilight lifted some manner of control panel from the table, pressing buttons with tiny clicking noises. The logos began to glow with green light.

“So, ah…” Rarity asked, playing innocent for fun. “What exactly is a ‘Portalbelt Thirty’? … and why is it glowing?”

Focussed on the device between her legs, Rarity failed to notice the other device that Twilight had lifted — another small box, with a seal shaped to fit over a pony's mouth, and three straps, one ending in a ring. In a single smooth motion, Twilight pressed the mask to Rarity's face, clipping the ring over her horn and buckling the straps around behind her head. The mask fit tightly in place, forcing Rarity's jaw open slightly and squashing her muzzle.

Feigning annoyance, Rarity twisted around, closing her legs together defensively and gesturing the mask. “Mmpfh!” she intoned in Twilight's direction. “Mm-mmfh.”

Twilight only grinned, biting her lower lip and perching herself on a futon in a relaxed, spread-legs position. Her member stood proud, bulging from its sheath, but for now Twilight focussed more on Rarity, and the control panel.

A button pressed, and Rarity felt the gentle tug of suction on her nipples. The moulded cups gently squeezed, suction rising and falling in a mechanical massage.

Another button pressed, and the device around Rarity's nethers emitted a mechanical *bleep*. She felt a brief prickle of static around the edges of her already aroused pussy, followed by the flow of cool air, as if the cover had been removed and exposed her. Twisting back, she spread her legs again to see what was happening, vocalising her muffled puzzlement. The glow had changed from green to orange, but from the outside there was no other visible change.

Then something pressed up against her folds. Something warm, hard, and fleshy. Rarity offered a tiny “meep!” of surprise, as the anonymous cock-head worked its way in between her lips.

…

Above the Sofas and Quills store, Davenport contemplated the pale grey dome resting on his bed. Twilight Sparkle had left it with him earlier today, explaining her plans and inviting him to participate. She'd sent him the go-ahead signal just under an hour ago, and he'd made himself ready and waiting. As strange as this device was, if it functioned as Twilight had described…

The dome bleeped at him. The one flat panel bearing the circular logo seemed to ignite with a boldly blue flame, and then the flames themselves swirled outward into a ring around the edges, condensing down into a rim of glowing magic, within which there was a hole, as if the surface had burned away to reveal the inside of the dome.

Inside, though, was not machinery but a quivering, dripping vagina. From the colour, Davenport could make a fair guess as to the owner. He smiled, testing the edge of the portal with his hoof. If he was going to be burned or shocked, better his hoof than his balls. The magic was hurtless to the touch, however. Satisfied of his own saftey, he brought his quite ready stallionhood to bear. Slowly and gently, he rubbed the head between the lips, lining up with the opening. He felt it twitch, the clitoris winking in anticipation.

Lowering himself onto all fours on the bed, closing his eyes and picturing Rarity's face. Then he began to thrust, burying his shaft deeply into her love tunnel, intent on making the fullest use…

…

Rarity gasped, and began to rock back and forth on the couch as the unidentified stallion drove his way deeply into her well-lubricated folds, immediately stretching her out and filling her up. With the portal affixed directly over hew marehood, her movements did nothing to mitigate the eager thrusting, and she could only do her best to relax into it, riding out the rough usage.

Her moans were interrupted when, with another bleep, a portal opened in front of her mouth.

Brow furrowing in trepidation, she turned her eyes to Twilight, who was grinning hungrily while lifting a grey cylindrical device into the air over her own penis. A blue glow from one end of the device illuminated Twilight's front. A few clicks, and Rarity felt small but hard metal rods push in between her parted teeth, forcing her jaw open further. Not wish to suffer more, Rarity relaxed as much as she could, and allowed the rods to pry her mouth open to its fullest. She continued to moan from the stuffing her pussy was receiving, only now she could hear the moans like an echo from Twilight's direction.

Twilight brought the tube down onto the end of her cock, and Rarity felt the member pass her lips and enter her mouth. Rarity stroked the head with her tongue, tasting the salty pre-cum. In slow motions, Twilight began to slide the tube up and down. With each stroke, Twilight's penis pushed to the back of Rarity's mouth, sliding over her tongue.

Rarity slumped back against the cushion, continuing to buck her hips helplessly around the shaft filling her cunt, and allowed her head to fall back so as to more easily accommodate Twilight's member. Twilight responded by thrusting deeper, penetrating Rarity's throat until she couldn't breathe, making Rarity gasp when Twilight pulled back, only to thrust in again before Rarity had a chance to recover.

Rarity was not a stranger to group sex, but she had never been so helplessly out of control, so thoroughly dominated. No matter how she twisted or turned, the belt and mask gripped her face and nethers, the cocks continuing to thrust into her mercilessly from both ends. Her eyes watered as her throat became Twilight's cocksleeve. Her vagina spasmed and her body twitched as orgasmic pleasure gushed from her marehood, and her lungs fought for air. Whoever was using her pussy was no quick finish, Rarity was well on her way to a second orgasm but he seemed no closer to finishing.

Some part of the device spurted thick goo over her anus, a nozzle pressing in to pump lube into her rear hole. She never heard the soft *bleep* over her own coughing and gulping, and the rushing in her ears, but she new what was happening next…

…

Big Macintosh was in his room, waiting to see if this box Miss Twilight had left with him would indeed function as described. When it bleeped at him and one face vanished in a swirl of blue light, he nodded and brought his head down for a closer look.

If that wasn't Miss Rarity's asshole, glistening with lube, shuddering as the surrounding muscles spasmed, then he was a filly. The thick stallion-meat swelling between his legs suggested that wasn't the case.

Satisfied that Miss Twilight's magic was indeed working like she said, Mac placed his hooves on the side of the box, gripping it firmly on the edge of his bed. He planted his hindlegs apart for stability, and raised his member to the proffered hole. He rubbed a little extra lube onto his shaft — a bigger cock meant more lube was well-advised — and leaned forward to gradually but firmly push his way in.

…

Rarity's eyes were rolling back. Her legs were attempting to vice-grip thin air, and were completely crossed as a result. Her backside was completely impaled, stuffed to her utter limit with big, thrusting cock, and Twilight continued to use her throat as a fleshlight. Orgasms wracked her body as her back arched, forelegs pushing her chest upward as though changing the angle of her body would help accommodate the dicks stuffing her.

In her vagina, the thrusting stopped, the stallion hilting his shaft, flare swelling up within her as cum pumped into her, only increasing the pressure. Seeing this, Twilight stopped holding back and picked up the speed. In moments, she was likewise pumping seed into the helpless Rarity, in this case straight into the mare's stomach.

Rarity thrashed helplessly as her lungs burned for air, dizzy asphyxiation threatening to overwhelm her, when Twilight pulled out into her mouth, cock still pumping seed faster than Rarity could swallow. She choked for air around the mouthful of cum, goo filling her nostrils and bubbling out of her nose.

Rarity collapsed back onto the couch. Twilight's cock was withdrawn and the bars holding her jaw shut had gone, but all she could do was gasp and moan as her belly bulged from the mighty cock filling her ass, continuing to thrust even after her pussy had been left empty of cock, but still dribbling excess cum.

When the stallion pumping her rectum finally climaxed, thrusting in deeper than Rarity had believed she could take, all she could do was wail helplessly and continually until the shaft was withdrawn.

With a final set of bleeps, the various devices returned to their neutral green glow, the portals closed as two satisfied stallions went to clean themselves off.

Twilight, meanwhile, unstrapped Rarity's mask, and joined her on the couch, kneeling beside her head.

“Clean me off?” Twilight said, slapping her slimy, half-erect cock onto Rarity's face. As far as Rarity was concerned, it didn't sound like a suggestion. Embracing her submissive role, Rarity opened her mouth and got to work cleaning. Twilight levitated over a bottle of water, with a straw. She dribbled it over her own cock, helping to wash off the other fluids into Rarity's mouth. When Twilight was satisfied with the cleaning, she slid off the couch and gave the bottle over to Rarity, who gratefully gulped the water down as Twilight took a damp cloth to wipe down Rarity's messy face.

Rarity was well aware that her hair and makeup were both beyond messy right now, but she could put up with post-coital messiness, at least until she had the strength to get up and deal with it properly.

“Are you akay?” asked Twilight gently.

Rarity panted, and nodded. “Yes, okay…”

“Great!” exclaimed Twilight, bouncing up and lifting a checkbox from the table. “It looks like everything is functioning well, and I've gathered plenty of data from phase one!”

Rarity's expression froze. Then her eyes slowly widened. “Phase… one, darling?”

Twilight beamed. “Oh yes. I mean, as long as you're okay with it. I'll give you some time to recover, and then we can try out the cleaning protocols, those will be essential if you're going to wear the belt for more than an hour or so, especially in this state… oh I have so many ideas, and a planned schedule of course.”

Rarity stared at Twilight. “More than…” she repeated weakly.

“Oh!” exclaimed Twilight. “We can go back to regular safewords, now. I mean, I can't expect you to stay on the couch all weekend.”

“All…” Rarity squirmed “weekend!?”

“Mm-hm,” affirmed Twilight. “I mean, if you don't mind helping me test out prolonged belt use. Just a couple of days should be enough for the tests I want to run, assuming of course I give you time to recover in between.”

Rarity lay back on the couch, eyes gazing unfocused through her ceiling. It wasn't as though she'd had any real plans for this weekend, but she had a feeling that two more days of Twilight's “testing” would thoroughly wreck her.

Well she couldn't say “no” to that now, could she?