This is written pre-canon for both Opaline and Misty, to the point where I'm not 100% sure that Misty is actually the unicorn's name. So don't bother me about canon errors.

[Edit: I guess canon Opaline is legit abusive, not just 'abusive for fun'. I like my version better.]

The BDSM activities depicted are exaggerated for erotic and humorous effect. Even if you or your partner somehow find yourselves in possession of a half-dozen penis tentacles, don't try this at home.

Opaline the wicked alicorn reclined on her dark throne, reflecting on her schemes. Her long hind legs lay draped over the edge of her seat, her slim torso nestled beneath the warmth of her purple wings, her face, aquiline while at the same time equine, rested thoughtfully on her forehoof.

Afternoon sunlight shone in beams through the blue stained glass of her throne room. As she watched motes of dust dance in the tinted light, she reflected on her goals, her plans, her powers. How far she’d come, and how far she still had to go.

Her evil plan was foalproof. Her machinations lay undetected. Her patsies were patsy-ing, her quislings quisling-ing, her Poseys Posey-ing. All the while, the clueless heroes of Maretime Bay enjoyed wacky friendship adventures together, untroubled by fear, unaware of any danger but an entirely manageable litter problem and what an absolutely terrible roommate Izzy Moonbow was.

Which was excellent. The enemy was unprepared, and that meant she was going to win. For once, evil would triumph.

But it also meant she was bored. She’d practiced her mind control and horn laser spells. She’d balance her checkbook and done her taxes. She’d checked her plan against the Evil Overmare list for the seventeenth time. There was nothing else to do. The temptation to move up her timetable just to make things more interesting was overwhelming.

But moving up her timetable meant she was more likely to lose. She didn't want to risk that!

She needed a hobby. The only hobby she had was abusing her minion, but it was a very good one. Where had that minion gotten to?

“MINION!” she roared, attempting to imitate the royal Canterlot voice written of in legend and lore.

“Ow,” said her minion, who had been sitting beside her throne doing sudoku. “You don’t need to shout, I’m right here.”

Opaline leaned over the edge of her throne and said “Minion, your Overmare is bored, and requires your consent to abuse you.”

The minion, a curvy, bright blue unicorn with a mane like strands of colorful yarn and a face like a fallen angel, looked up at her with dancing green eyes and said: “I have a name, you know.”

“It pleases your Overmare to call you ‘minion’. Especially when she is horny. In ancient times, the term had a homosexual connotation. Isn't that interesting?”

“I was unaware,” said Misty the minion in a tone that suggested she very clearly remembered that fun fact from the million other times her Overmare had informed her of it.

Gracious, Opaline ignored the subtle disrespect. She rested her magnificent jawline on the arm of her throne and lowered her eyelids seductively. “Your consent. I demand it.”

“That isn’t...” Misty covered her face with both hooves. “I told you, that isn’t how that works.”

Opaline pouted. “Please? Pretty please?”

Misty closed her sudoku book and pushed it aside. “Fine, fine, I’m done with those pathetic puzzles anway. What did you have in mind? Did you want me to suck your teats and call you mommy?”

Opaline threw back her head and laughed her villain laugh. “Oh no, my precious filly. I had something a little more... intense in mind.” Her curved horn glowed as she cast her favorite spell. A spell of transformation based on one created by Twilight Sparkle herself.¹ Her marehood unfurled as her clitoris extended into a cock. A strange-looking cock, asymmetrical, with a forward-tilted flare and a number of oddly-placed lumps and ridges. Six tentacles slithered out from her sides, glistening, lined with suckers, and tipped with wide, oozing flares.

Misty watched the tentacles with fascinated horror as they crept over the throne towards her and shrieked as they lashed out to grab her. They whipped around her tummy, her hind legs, and her mouth, and lifted her struggling body into the air.

Are you okay with this, sweetie? said Opaline telepathically.

Very yes. Don’t stop, and don’t be gentle. Please. My Overmare. I love you so much.

I love you too, but don’t say it out loud. You’ll ruin the mood.

Opaline's tentacles slid over Misty's body like snakes. The suckers pinched her every soft curve and delicate fold, leaving behind magical hickeys that stung with a subtle pain like music and glowed pink and purple through her silky blue coat. The tentacles oozed a natural lubricant that left Misty’s previously immaculate fur matted against her skin. “Let me down,” she whimpered, almost sounding like she meant it. She twisted against the tentacles, feigning terror, testing their incredible strength.

Opaline dragged a tentacle across Misty’s lips, caressingly light. “But why, my precious minion? You’re so wonderful to touch. You have such a delightfully round tummy...” The two tentacles wrapped around her middle and squeezed. “...and such a deliciously plump and spankable ass.” A tentacle slapped her rump cheeks, making the soft flesh jiggle. Misty squealed in alarm and pain and clamped her tail down over her delicate bits. Opaline cackled and yanked her tail up harshly. “What do you think you’re doing? Every part of your body belongs to me, filthy minion.”

She brought her tentacle down on Misty’s pussy and ponut with stinging force. Misty’s shout of pain and the tears that shot down her cheeks were unfeigned. The tentacle came down, again and again, making the smooth skin of her delicate parts burn and sting. When it stopped, the tentacle's flare massaged her pussy and asshole, rubbing unkindly at the puffy, battered flesh.

“Every part of your body belongs to me. If you attempt to deny me, you will be punished.”

Misty shivered in bliss at the cruel words, trying to disguise it as a shudder of shame and revulsion. “I’m sorry. I’ll try to be good. But you’re getting my pretty coat and mane all icky,” Misty whimpered. “Please stop.”

Opaline released all of her tentacles except the one holding Misty’s tail. Her weight tugged unpleasantly on her tail root, and she swung back and forth in front of her mistress. She had to roll her eyes up to look at her.

“Oh. You’re afraid of getting dirty, are you?” said Opaline. Her lips pulled back from her shining white teeth in a predatory grin.

“Very. I hate being dirty. I hate it so much.” Contrary to popular belief, a lie does not become true if you repeat it often enough. Misty told this one very often, sometimes as often as three times a day. The intent of the lie was to make the thing she was asking not to happen, happen. It was a fascinating paradox.

Opaline shook her by her tail. She squealed in fear and pain. Two tentacles slid up her back and over her buttocks. Strong coils circled her thighs and squeezed deep into fat and muscle. The flare of one wiggled in between her thighs; the other rubbed up and down her ass crack.

“Overmare... Overmare... what are you doing? It feels so tingly,” moaned Misty.

“Like you don’t know, you disgusting little slut.” Opaline arched her slim body sensually, writhing against her throne. “Oh, your silky little body feels so good against my tentacles. Tell me. Are you my little tentacle whore who thinks of nothing but unnatural penetration, day and night? When I’m not with you, do you rub your little pussy raw thinking about me using you, wishing I was here, longing for my insatiable desire for tentacle sodomy?”

Misty gasped. “No! Overmare, no! I’m a sweet little pony and only have pure thoughts! I hate what you do to me and long for release from the yoke of having to satiate your vile lusts! I’m traumatized by it! I cry about it in therapy so much that my therapist bought stock in the tissue company!” All of these things were lies. The exact opposite of true. Though Misty’s therapist often expressed concerns about her relationship. And Misty did cry in therapy, but mostly about how all the sudoku she could find were too easy.²

Opaline lashed Misty’s hind legs together with a tentacle and rubbed the sensitive skin of her tentacles between them, enjoying the delicious texture of her slimy fur, her slick, leathery pussy, and ponut, the delectable jiggle of her ass cheeks.

Misty, helpless, hanging by her tail, lost herself in the shame and glory of being frotted by the greatest alicorn in history (give or take four or five). The pace of the tentacles thrusting quickened, the slick, muscular organs of pleasure pulsing and secreting with lust.

Overmare, may I play with my pussy?

Always, you revolting little tentaclesucker. I love to see it.

Magical energy rushed to the tip of Misty’s horn, and she rubbed frantically at her clit with her telekinesis. Joy bloomed between her legs as she mashed her little heart-shaped bud back and forth. She realized that she could cum at any moment, but slowed her rubbing, wanting to cum when her Overmare did. Lust burned in her lower body, but she willed herself to control it, knowing it would only grow more intense, more delicious, for having its satisfaction delayed.

The pulsing of the tentacles between her ass cheeks and her thighs quickened. They mashed their tips together, twisted around each other into one long log of lust. Heat radiated from them. Their thrusting lost all rhythm. Misty looked down at the magnificent alicorn on the throne beneath her, admitting her slim figure, her perfect hair. Her intelligent eyes were utterly enraptured by her, Misty the minion, an utterly unremarkable mare. How had she been so lucky?

Opaline’s lover’s wings unfurled to either side, revealing a wingspan large enough to envelop four of Misty. “Oh! Discord!” she screamed. “I’m going to cover you, you nasty little spunk strumpet!”

The tentacles thickened as their load pulsed through them. Misty felt the hot, sticky seed well up out of them. It arched up into the air, splattering her tail and then plopping down in ropes and dollops on the back of her thighs and buttocks. The tentacle between her ass cheeks pulled back to squirt over her pussy and asshole.

Misty pushed down hard on her clit. Fireworks exploded behind her eyes.

“Fuuuddge that felt good,” whispered Misty.

The tentacle between her ass cheeks wiped its flare on her dock and slapped her across the face. “Did I ask you how it felt, minion?”

Misty whimpered. Overmare had not put her full strength behind the slap, but it still stung. Her hoof twitched to rub her cheek, but she knew that would provoke additional punishments, deliberately on the edge of what she would enjoy.

“Now,” said Opaline, her tone dripping like honey with that mix of satisfied desire and barely-controlled lust that only a near-goddess with seven cocks and the stamina of an immortal could manage. “What to do with you next?”

“Please don’t put your tentacles all the way through me,” said Misty in a high-pitched tone that she hoped approached terror. “I hate it when you do that. It’s horrible.”

She winced as another slap stung her cheek. The spent tentacles holding her tail tossed her in the air. Misty squeaked, weightless for a delirious second, droplets of cum hovering in the air about her. She started to plummet, and then stopped with a jerk as Opaline’s spent tentacles snapped out and wrapped around her hind pasterns. They jerked them far apart, allowing another tentacle to slap her on the pussy. It came down, again and again, pressing past ‘fun’, into ‘barely tolerable’, and then into...

Yellow! Yellow!

Opaline’s thoughts had a growling tone. What did I tell you about topping from the bottom?

Misty blushed through the coating of tears on her cheeks. Never to ever do it or you’d spank me into a coma?

That’s right. Luckily for you, I love going all the way through you too, and I’m not going to deny myself just to punish you. However, I’m starting to realize that if it only provokes a ‘yellow’ safeword, then spanking is not a sufficient deterrent for you. You’re demoted to scullery maid for a week.

Misty’s heart sank. What?! No! Seriously?

As serious as sin. Which you should know I take extremely seriously.

Oh, pickles! Can I at least wear a cute little Prench maid’s outfit while I do it?

If you don’t mind getting greasy slop water on it. Now. Let me focus. The four tentacles that still bore loads oscillated back and forth before Misty like charmed snakes, except that in this scenario she was the one who was helplessly fascinated.

Oscillate... Oscillate... Oh! Overmare! How do you tiliate an ocelot?

Misty, no.

You oscillate his tit a lot!

Four tentacles flew towards Misty’s fat little teats, smacking them hard.

“Ow,” said Misty softly.

You’re incorrigible.

Overmare never forbade bad jokes.

Well I do now. Especially that one. Tell that joke one more time and I’ll throw you to the diamond dogs.

Diamond dogs are extinct.

I’ll resurrect some just for you, and I’ll make them extra horny.

Don’t threaten me with a good time.

Yes, actually, that does sound like fun. I’ll make a note of that one. ANYWAY, you’re spoiling the mood. Where were we?

“Oh, my Overmare, please be merciful. I’ll do anything you want, just don’t hurt me anymore.”

Opaline caressed Misty’s lips with a drooling flare. “Well, but there are four tentacles left, and you only have two filthy holes.”

“Um, I have three...”

A tentacle bapped her on the nose. “What is our rule.”

“Um... Pussies are for princesses?”

“Yes. And are you a princess?”

Misty smirked. “No. I am a filthy minion. In the homosexual sense.”

“That’s right. Now. No more backtalk from you. Use your mouth for something better. Open wide and say ‘aaaaahhh’!

Misty braced herself for the wonderful ordeal she knew was coming. She opened her mouth for Opaline, so wide she could see rear molars and uvula. “Aaahh... MNGH!” She trembled as two fat flares squeezed their way past her lips. Tentacles had many advantages over cocks. For one thing, they were supple. Cocks were stiff and inflexible—or at least magical marecocks; Misty had never been with a stallion and at this point couldn’t see how one could possibly compare with Opaline. She was ridiculously spoiled. Tentacles could compress to fit through tight holes and then expand to fill interior spaces to bursting. This was exactly what the two tentacles did now, penetrating her delicate beestung little lips, stretching her jaw, and puffing out her cheeks.

Inside her mouth, they wormed around each other in a spiral like mating mollusks, compressed, and slid into her throat. The ease with which they did so left Misty with an unsettling yet crotch-soaking feeling of loss of control. “Mnngghhrgle...” she moaned, twisting in her lover’s grip. Though she’d done this dozens of times, the feeling of pulsating flesh probing deep down her throat still created as much anxiety as it did pleasure. Oh, but what a strange and wonderful pleasure it was, feeling the mare she loved so deep inside of her, stroking places no other could reach with twisting muscle and pinching sucker.

But when it came to pleasure her throat was nothing compared to her ass.

The wide flares of two tentacles folded themselves down to pointy bulbs and fondled Misty’s deep blue pucker, stroking the puffy folds, dripping sex goo onto them. Misty pushed down with her inner ass muscles and winked her donut-shaped cerulean flower. The flare-bulbs dove in like hungry wolves, dripping natural lube, massaging open the muscular ring of her anus. Inside, the flares bloomed, spreading her fluted inner walls, caressing, advancing, gradually thickening. A feeling of fullness suffused her bottom. Misty like her ass stretched to its limits, and her perverted, horny Overmare was only too happy to fulfill that desire. Her tentacles slid deeper inside of her, thickening as they went, filling her colon, getting fatter and fatter until Misty gave the telepathic signal that the feeling in her ass was starting to move from delicious ache to worrying pain.

And then widened her tentacles just that teeny, tiny bit more.

Inside Misty, the tentacle tips rushed through her large intestine, then shouldered their way into the tight confines of her small intestines. They found the way clean and clear, with no obstructions. Opaline took great care with the anal health of her toy; washing her with regular enemas and feeding her on a selection of magical nectars and herbal teas, so that her insides would never have to trouble themselves with something as quotidian as the digestion of food. Every inch of those delicate tubes was reserved for her Overmare’s pleasure.

And Overmare took that pleasure, pressing in, feeling those silky, delicate inner walls stretch with her passage, the skin of her tentacles tingling. She fed more and more of her length into her minion, squirming with the unspeakable pleasure of using another creature’s entire digestive tract from front to back for one’s own selfish sexual gratification.

Her four tentacles met at Misty’s stomach like the spearheads of a conquering army closing on a nation’s capital. They pushed ungently through the stomach’s sphincters and tangled around each other, four flares rubbing together and intensifying her already near-unbearable pleasure.

Misty’s body spasmed around her, throat and anal ring clenching down. Quick as lightning, Opaline—ever a helicopter dom—checked the biometric spell to confirm that her plaything was, in fact, cumming and not dying. Her stomach dropped when Misty’s heart literally missed a beat, but when it started again at a ferocious patter, Opaline’s tentacles pulsed with impending ecstasy. She opened a one-way empathic link to Misty so that when Opaline came Misty would be able to feel every second of her Overmare’s pleasure.

She thrust her tentacles wildly, driving them into Misty, four flares bashing against each other. Energy built in the tentacles, a crackling, pulsating electricity that drew joy like gravity to itself until it burst into a white-hot supernova of desire. Rope after rope of cum shot into Misty’s poor tummy, filling it, then inflating it like a balloon, pumping and pumping like a faucet tap.

Misty’s mind cleared from feeling the after-effects of Opaline’s orgasm to find her tummy distended and sloshing with cum. She placed her forehooves on her belly and slid them over its curves, groaning with satisfaction. It was so large it seemed like she might be pregnant.

With quadruplets.

Oh, Overmare, I think this might be your biggest load yet.

I’ve been working on my volume. She pulled her tentacles out of Misty’s throat with a pop; thickened spit and a shocking amount of cum poured out afterward. Especially shocking considering the amount that was still trapped in her tummy. The river seed running from Misty’s mouth was just overflow!

Misty gasped for breath. Her whole body trembled helplessly. “Oh, Discord. Oh, Discord. ”

Opaline began to pull her tentacles out of her ass. It was a delicate, involved proccess; more dangerous, in fact, than going in. She needed to leave everything as she found it to prevent injury. Misty sighed with regret as the tentacles slid out of her ass. She felt saddened by her gaping ass, missing her lovers’ tentacles as her body slowly closed up behind her. The ass tentacles pressed their deflated, dripping flares to her lips to be cleaned, which she did with alacrity, smelling the faint, not-unpleasant musk of her scrupulously clean ass on them.

“Did you like that?” purred Opaline.

Are we in character? Because it’s going to be really hard for me to say I hated that.

“No, my precious princess,” said Opalie, smiling blissfully up at her. “We’re done with pretend time. No reason to act like you’re anything but the endlessly thirsty slattern I know you are.”

Misty put a hoof against her chest; she could feel her thumping heart through her ribs. “That was amazing. Incredible. It literally... literally gets better every time we do that.”

“An impressive statement, considering we’ve done it three hundred and forty-three times, my princess.”

“Oh, way more than that.”

“I meant with the tentacles, princess. We’ve taken pleasure to the point of orgasm one thousand, seven hundred twenty-nine times in the course of our relationship. And I’m up to increase that by one if you have any energy left in your frail mortal body.”

Misty's eyes widened. “You keep calling me princess. Does that mean...”

Opaline smirked and nodded. She set Misty upright in her lap; felt a flood of cum pour out of her ass and across her thighs. “Pussies and pricks are for perfect pony princesses. It would please me to pound your pudendum into pudding.”

Misty giggled and draped her hooves high up over her Overmare’s shoulders. She scooted her hips forward and rubbed the forward crest of her pussy against the strange, bumpy shaft. Opaline’s cock looked strange because she’d taken months modifying the old fertility spell she'd made it with, lovingly fleshcrafting it to be a perfect fit for Misty’s pussy. Shaped to her insides, thick where she needed to be filled, and thin where she might be hurt. The flare tilted to bump her womb hatch without ramming it, hurting just as much as she liked it to and not a smidge more. Rough spots and hard ridges studded its shaft, placed where her nerves were most sensitive. Misty bucked her hips against its relentless hardness. “I want to ride it,” she whispered.

Opaline arched her long neck downwards and locked her lips over Misty’s in a deep, aggressive, drooly kiss. She scooped thick ass up in her forehooves, and they sank deep into its magnificent lushness. She lifted her pussy over her flare. Misty pushed her hips down and slid her dripping pussy over Opaline’s cum-slicked pink cock. It popped right inside, just as it had been designed to do. She gasped with pleasure as the marecock filled every curve and crevice of her cunt. Opaline groaned at the sudden hot, slick, silky goodness enveloping her dick. She arched upward pressing it in deep to Misty’s most personal spot, claiming it completely.

The two of them writhed together, moving as one, their bodies slapping and squelching, Misty’s cum-pregnant belly bouncing and jiggling between them. Sweat rolled in rivulets down their bodies, leaving dark trails through their fur. Opaline wrapped her spent tentacles around her legs, ass, and barrel, holding her tight, feeling the bounce of her butt, the twisting of her thigh muscles, the rapid rise and fall of her ribcage as she breathed.

“I want you to fill my womb,” Misty moaned.

Opaline giggled. “That’s not how that works, you know.”

“It can for us. I want a womb full of cum like my tummy is full of cum. I want you to put your foal in me.”

Opaline whispered in Misty’s ear. “Beg for it.”

“Breed me,” groaned Misty. “Make me your broodmare.”

Opaline’s hips jammed up, slamming her flare against Misty’s womb hatch, making her scream in pleasure and pain. Unicorn cunt muscles slammed down on her dick as her minion came hard. “FUDGE! PICKLES! DISCORD!” wailed Misty, tears of joy rushing down her cheeks.

Opaline's magic massaged Misty’s cervix, dilating it enough that when fire rolled through her belly and cum pulsed out of her cock it sprayed the inside of her womb like a firehose. Excessive amounts of seed splattered her inner walls, pulsing, filling her, stretching it, making the lower part of her belly balloon out to match the top part. so that she resembled a blimp as much as she did a mare.

“I love you. I love you. I love you,” whispered Opaline, stroking Misty’s mane, sweaty, shaking.

“I love you so much,” groaned Misty, laying her face against her Overmare’s chest, burying her snout in her soft ruff of fluff.

Opaline’s horn flickered anxiously. All that talk of breeding. Was Misty entering heat? What would a foal mean for her evil plans? Foals took a lot of attention. What if being a mother left no time for evil? Her cum was real cum; not a prop. She couldn’t get the spell to work any other way, and honestly, she wouldn’t if she could. She was earth pony, unicorn, and pegasus; why couldn’t she be both male and female as well?

A wicked thought entered Opaline's mind. She could sweep Misty’s womb for eggs. If there was one in there, she could precisely remove it before it was even fertilized. No foal, nothing to distract from her evil plans.

She visualized the spell matrix to make that happen. There was, in fact, an egg there, swarmed by sperm trying to batter their way in. She tried to cast the spell to destroy it but found she couldn’t will herself to do it.

All the times she and Misty had made love, she had soaked the little blue mare’s insides in cum, and nothing had happened yet. What if this was the time? And what if she ruined their only chance to have a foal?

She had so many evil plans. But at the back of her mind was the suspicion the world needed two more good mothers more than it did one more evil Overmare. She let the matrix drift out of her mind. She would do nothing to help or hinder Misty's fertility unless Misty asked her to.

Broadcasting on a tight beam, so that Misty wouldn't detect it, she said Good luck, little egg.