It was midafternoon on possibly the third day of Spike’s incarceration. At least, that’s what the clock said. Truth be told, it was hard to keep track of such things when you kept passing out from exhaustion, only to wake up an indeterminate amount of time later because your oversensitive naughty bits were being stimulated. Feeling oddly lucid at the moment, Spike decided to investigate something. Moving the arm wrapped around Sweetie’s middle sent a domino effect through their elaborate bindings and resulted in him unintentionally twisting his double dick into her sore cunt. However, just about everything either of them did had that effect, so there was no choice. It took a lot of effort to move his arm and confirm his suspicions. Not only was he sticking to Sweetie through their shared sweat, but a noticeable groove had been left in her fur, and possibly the skin beneath.

“Heh. Our bodies are fitting together in all kinds of ways. It’s like we’re fusing together,” he chuckled weakly.

Sweetie only gave a mewling whine, which Spike interpreted as acknowledgment. He wasn’t sure if she understood what he’d said or had simply heard him. It was possible that she was already too far gone and had already been fucked stupid. Thinking that gave the drake a slight bump in pride for having accomplished this. However, Spike optimistically chose to believe that she’d not only understood, but responded in the affirmative of his weak attempt at levity. Regardless, as time passed, the youngsters’ movements caused their privates to tease one another. Tension built and their bodies eventually gave in.

Meanwhile…

Downstairs, to call Rarity distracted would be an understatement. Here she was with a very important client, discussing a very expensive order, and her dick was hard. That wasn’t the bad part. Most ponies would take such a display as a compliment, or at least appreciate the eye-candy. What made the matter inappropriate was that Rarity wasn’t hard for her client, but the youngsters in the scrying window that she kept stealing glances at.

“Hmm. You know, you could just move those two down here,” Sapphire Shores suggested, snapping Rarity back to the present.

“Beg pardon?”

“Down here. You could set them up…” Sapphire trailed off as she surveyed the lobby. “Right over there. It’s close enough to the entrance to be the first thing that customers see. Surround them with a few marequins sampling your work, and I guarantee it’ll boost your sales.”

Rarity gave the matter its due consideration. “Interesting. I’m working towards recapturing the lost art of sex beyond exhaustion. Putting the specimens on public display would add to the humiliation and further their cries of woe.”

Sapphire set a hoof to her chest and swooned. “A mare after my own heart. So tell me. Is that fifth leg also display-only?”

Rarity’s expression shifted from thoughtful to sadistic. “I was wondering when you’d ask.” The unicorn pounced on the earth mare and knocked her to her back. Sapphire giggled excitedly as she pulled her front hooves in. The window was maneuvered so that both mares had a clear view of Rarity’s ‘art’ before she dropped down. Rarity smashed her lips to Sapphire’s while her cock was pressed tightly between their bellies and teats. As the unicorn ravished the earth mare, hurrying through her usual level of foreplay, both could hardly tear their eyes or ears away from the window. Rarity adjusted the second window to start orbiting the youngsters, giving prime views of everything worth seeing.

With everything set, Rarity lifted her rump into the air, lined everything up with her magic, and dropped her cock with the force of a falling boulder. Sapphire squealed ecstatically as she was penetrated to the base in a single swift motion. She embraced Rarity tightly and expressed her gratitude through needful kisses to the neck. Her primal fires stoked by the sight of her younger sister and part-time assistant in such a state, Rarity wasted no time jerking her hips back to begin pounding some pussy. The sounds Sapphire made were so lewd and uncouth, which only increased Rarity’s longing. This was a good hard fucking, like the kind she’d suggested to Spike, only without the exhaustion.

At one point, as the window rotated around the pair, Rarity locked eyes with Spike. He was conscious of her and her actions. She could see the understanding in his eyes. He knew that she was taunting him by fucking a mare of her own accord while he had no choice. His lips pulled back as he bore his teeth. Giving a beastly and guttural cry, Spike bit down on Sweetie’s neck and renewed his pounding into her, seemingly catching his… Rarity estimated his 24th wind. She was so proud of him for his wise choice to simply give in. Surely he must have picked something up from Twilight’s lessons with Molestia. The indulgence of one’s base urges mattered infinitely more than silly things like pride or even physical ability.

As a reward, Rarity adjusted the window on her end to give Spike a better view of the other acts of carnal bliss taking place under her roof. Her frantic jackhammering slowed to a more reasonable pace for her audience. Sapphire seemed to appreciate the chance to breathe, but otherwise did her best to maintain a reasonable pace. The earth mare grabbed around the unicorn’s neck, pulled up in time with Rarity’s withdrawals, and slammed her hips back to meet each thrust. When Rarity came, it was with an explosive impact that sent drops of juice spraying everywhere. Sapphire was swearing up a storm that not even Rarity’s kisses could quell. It was just so very dirty, and she loved it.

Upstairs, Spike had also climaxed. This one was particularly strong as it lasted for several seconds, even if he was pretty sure he’d just ejaculated damp air. His senses must have also been jacked up, because that one felt especially good compared to the others today. Even Sweetie’s bleating moans sounded particularly appreciative, despite also having run low on fluids. The youngsters had been at this for so long that all else had been forgotten. There was only the ongoing pleasure of fucking, broken up by brief periods of rest, replenishment, and then it was right back to the tugging. Whether they liked it or not, the binds would always tug them in just such a way that ground them together in a most enticing manner.

Resistance had been forgotten. Escape had been forgotten. Their names had nearly been forgotten. There was only the bliss of the moment. Spike didn’t even bother to take advantage of the respite and just kept moving his hips. Maybe a part of him had picked up that willfully slamming his hips into Sweetie’s plot was less taxing than what the bindings did. However, more likely it was that he’d reached a point where he was too exhausted to do otherwise. All non-essential brain functions had been shut down to focus on the filly. She felt so soft and warm and her cries of want were exhilarating. He need not be concerned with anything else.

Sweetie had reached this conclusion some time ago. It was easier to surrender to the demands of her hormones. Spike’s rimmed hemi-penis slamming into her pussy was the best thing ever. Each penetration made her feel so full and even the withdrawal of that fullness heightened her bliss as the ridges scraped along her walls. But without question, nothing beat the raw ecstasy of Spike’s climaxes. Her whole body shook as her pussy clamped down hard and milked his dragon cock for everything that it had. Even when there was nothing, it still triggered a rush of endorphins that sent the young mare over the moon. She loved this. She loved this so fucking much and she wanted it to never end.

Then, some immeasurable amount of time later, the binds came loose. The youngsters were still clinging so tightly to one another that they failed to notice right away. Even seeing the silken ribbons encased in blue magic fly around them before being set on the shelves was barely a blip on their sex-addled minds. And when gravity mixed with weakened muscles to finally pull them apart, they still failed to register that anything had happened. The absence of the others’ warmth was jarring, to say the least. Both started groping at the air and whining as they sought the familiarity of reunification.

“Ah-ah, my darlings. I think that will do.”

Weakly, the youngsters stared up at Rarity and tried to vocalize their protest, making incomprehensible gurgling sounds instead of words. The white mare looked back at them with her sweetest smile and, as she’d been doing for the last few days, guided them into eating and drinking.

“No stimulants this time, darlings. No drugs of any sort. Sweetie, I am beside myself with joy to inform you that your heat… has passed!” Rarity threw her head back in a flourish. “Congratulations!”

“Uh…” Sweetie tried to reply.

“How do I know, you ask? Well, it’s all a matter of smell, darling. I suspect that you two have gone nose-blind to the overwhelming stench,” she purred huskily, “of sex that has permeated this room, I can assure you that the rest of us can detect the change. The pheromones of a mare in her receptive state have gone away, and much sooner than I’d expected,” she said while thoughtfully touching her hoof to her chin. “But I suppose it doesn’t matter. Since Sweetie’s heat wrapped up early, I see no harm in giving you two a day or so to recuperate. Rest, stretch your limbs, and hopefully regain the ability to form coherent sentences. Other than that, I’d just like to once more offer my congratulations on working through your first heat, Sweetie. And thank you sincerely, Spike. You and your fabulous penis have done splendidly.”

The youngsters were only able to follow every other word. Their bodies still moved in auto-pilot, humping into the air long after any reason to do so. It even took them a while to try and fumble their way back towards one another, but alas, their atrophied muscles wouldn’t allow it. At least they were able to hold hand and hoof in a show of solidarity for their shared ordeal.

Time passed, and without the constant stimulation of forced fucking overwhelming their senses, the youngsters slowly started coming to. One-by-one, the lights upstairs flickered back on. Sight was more than just light and movement, but distinct shapes and colors. Spike’s claw was sharp, potentially even dangerous, yet Sweetie felt safe and reassured in his grasp. Sweetie’s smell no longer compelled Spike to fuck until his hips were sore – at least not as much – and yet he still felt drawn to its subtle sweetness. Eventually, the pair were able to crawl and tug their way into one another’s arms. The warmth quieted their anxiety as they studied the textures of the other’s body.

“S-Spike,” rasped the filly.

“A-ah… I’mmm heeere,” croaked the drake.

By the next morning, the two youngsters had made a remarkable recovery. Spike could stand a whole five seconds before collapsing while Sweetie’s wabbly legs held for almost half a minute. The first real sleep they’d had in days did wonders for their mental states. When Spike fell, Sweetie was lucid enough to laugh before moving to help him up. They barely even thought about sex, contenting themselves with gentle nuzzles and the odd friendly grope. Sentences were still awkward and disjointed at times, but they got their points across.

Rarity visited more frequently to check in on them instead of just to serve meals. She offered words of encouragement to stand for as long as possible, and then to go a little longer. She coached them through sentence formation with the patience of a proper teacher. When they did especially well in overcoming hurdles, fashion horse rewarded them with tastings of her cock. Magical futa cum had rejuvenating qualities… apparently. Rarity loved lying on her side and letting the marginally regressed young adults suckle at her penis like it was a teat. It was as naughty as it was maternal.

However, on the last day of recovery, when Spike was finally well enough to walk back to the treebrary on his own, Rarity confronted the young pair with her suspicions. “Oh, Sweetie. I have the most fabulous news. It’s just… Oh my.” She fanned herself. “I just made myself dizzy.”

“What’s the matter?” asked Sweetie as she came up to Rarity’s side without a trace of reservation or resentment for prior treatment. Being raised with Rarity, Sweetie knew what her sister was about, and rather liked it.

Rarity summoned a glass of water to drown her excitement. “Goodness. Beg pardon. It’s just… Oh my!” She cleared her throat. “Sweetie, do you know why mares go into heat?”

Sweetie became thoughtful. Over the years, she’d heard a great deal of talk about heat, about how it was amazing and awful all at once to go through a solid week of nonstop sex, but not a lot about its purpose. When Spike cleared his throat, she answered, “Uh, can I call a friend?”

“Of course,” giggled Rarity as both unicorns look to the drake.

Spike smirked at the chance to show off his smarts. “Heat is that time of year that a mare becomes receptive. She puts out hormones to attract males to… to…” From the outside, you could almost see Spike’s brain hamster stumble, fall, and be sent flying right off the wheel. “Uh-oh.”

“Receptive to what?”

“To a stallion’s seed, darling,” answered Rarity. “Sex is about more than just fun and social cohesion. It’s how we maintain and propagate the species. You and I only exist because our parents forged the beast with two backs while mother was in heat. Now, I was suspicious when your heat ended a full two days early, so I ran a few tests.”

“Sweet Molestia, why?” Spike whispered in dread while Sweetie remained oblivious.

“And they came back positive!” Rarity cheered before sweeping her sister up in a bone-crushing embrace. “I’ll admit that it was a bit of a longshot with Spike being a dragon and all, but this is still a wonderful surprise. I’m going to be an auntie!”

It took Sweetie another seven whole seconds before the dots connected. “But I’m you’re only sister. So if you’re an auntie, that would make me…” Her pupils shrunk to pinpricks.

“That’s right, Sweetie. Oh, you’re so lucky. You got knocked up on your very first heat, and with a dragon, no less. I’m so happy for you!”

Sweetie didn’t know what to feel. She’d only recently recovered enough cognitive ability to process complex emotions, but this would have been a doozy even on a good day. She was aware of Rarity’s hoof drawing circles over her belly, but it still took a second for the implications to sink in. There was something in there. Sweetie Belle… had a life inside of her. “I… I’m gonna be a m-” Her voice hitched in her throat. “A mommy?”

“That’s right, darling. Oh my stars! That would make Spike my brother-in-law. How… delicious,” she purred.

For the first time in days, Spike’s cock twitched back to life. His eyes tracked to where Rarity’s and now Sweetie’s hooves were touching. He’d done that. Sweetie had been knocked up… by him. “I… I’m gonna be a daddy?”

“Oh, yes!” Rarity cried out in joy. “Trapped for days on end, with nothing to do but fornicate like wild beasts until even your minds erode, and born as a result of this coupling is a… a… Hmm. What do you call an infant hybrid of a dragon and a pony? Will it be an egg or live birth? Oh well. I’m sure that Twilight knows. What matters is that it’s a story straight out of a bestselling romance novel.

Expression blank as though in a trance, Spike walked up to the ponies with his claw extended. With conscious gentleness, he reached out and touched Sweetie’s belly. Her fur was soft and his body was warm. Logically, he knew that it was still too early to actually feel anything. However, the pounding of his heart echoed so deeply that he could have sworn he heard the faintest pitter-patter of something else. Spike looked up and met Sweetie’s eyes. The youngsters and soon-to-be-parents shared an awkward smile, and then they kissed.

Sometime later…

“WHAT THE FLYING FUCK!!!?” inquired Trixie and Twilight in the most civil manner one might expect from them. Only a third of the town burned down while Molestia pissed herself from laughing so hard.

Author's Note

And thus, we conclude our little tale. I hope that everyone enjoyed it, although I know that this is a super niche kind of fetish, so likely, this won't be for everyone.