Thunderlane stared at his dick: it was definitely a bit larger than when he'd went to bed last night, with accentuated veins and balls to match, twitching insistently. "Oh no... this is bad..." He realized Spitfire really must have been infected. For some reason that didn't bother him as much as he felt it should have - it just made the whole thing more kinky. He reached a hoof down to inspect it, brushing against the side lightly. "Hnrk!" It slapped up hard, flared, and coated the mirror with cum, slightly green in its consistency. Had he just become a spore dispensary for those damn tentacles?

As the adrenaline wore off, Thunderlane realized just how absurdly horny he felt. He turned to his bed in trepidation and noticed that a good half of the sheets were plastered with the same green goo. Thunderlane remembered having a couple wet dreams last night, but he didn't think it had been that bad. He must have been cumming practically all night! Thunderlane felt woozy, and propped his forelegs up on the table outside the bathroom, his hips thrusting involuntarily, his plantlike penis tingling intensely. He realized he was thinking about Spitfire's ass. He tried to think of her pussy instead, but it just didn't seem as sumptuously appealing.

He looked to the clock. "not much time..." The Wonderbolts were moving out in about half an hour to torch the vines.

Thunderlane frotted the underside of the table anxiously, then grabbed his cock in his hooves. He was so devastatingly horny he couldn't help but masturbate, so he rationalized it. He had to get this out of his system: surely draining more of the infectious spores would be a good thing before he left. He'd have to deal with it for now and get it checked out after they were done. The safety of the equestrian citizenry hung in the balance after all! Every minute counted.

"Gaaahh!" Thunderlanes enhanced nuts lurched up violently as he painted the underside of the table with his cum. He wandered unsteadily towards the kitchen to grab something to eat, but as he reached the fridge, he couldn't help but lean against it and masturbate again. By then there were only 20 minutes left to meet up with the team. After a few more orgasms, and only 10 minutes remaining, Thunderlane realized this wasn't working: if anything, his dick felt needier than before, and his balls felt even more packed with cum. He shook away the invasive mental pictures of Spitfire's ass and jumped in the shower, turning the water on cold - if it helped with his newfound libido, he didn't feel it.

With a groan, he stepped out to dry himself and suit up - 6 minutes left: just enough to speed over, but not much margin for error. He'd just have to find a way to ignore his maddening needs until after they'd dealt with this - he had to.

"Aaaagh... Come on!" Rainbow Dash whined as she plunged against the dildo she'd stuck to the wall. Rainbow's anal hunger has only gotten worse since yesterday, From an itch, to an emptiness, to an involuntary clenching, twitching starvation.

"Haah... Ok, one more and I'll start my workout..." She sunk back against the dildo, shivering in delight, mane unkempt slicked with sweat. If she were in a different mental state she might have joked that this was her workout, but all she could think of right now was the cathartic cylinder rubbing deep inside her ass.

She'd definitely have to get this checked out, after they torched those plants. The safety of the ponies of Equestria needed to be the top priority here! As long as she wrapped up quickly here, she'd be able to tough it out for a few hours and get the job done, surely. Her mind shorted out to white static as she savagely came again, shivering beads of sweat off herself and spraying marecum all over the place as her ass desperately clenched attempted to milk the vine - no dildo - for everything it was worth, the whole experience rocking her to her core.

Vine? Where had that thought come from?

Rainbow clenched her eyes shut as thoughts of vines rimming her ass before plunging in assaulted her mind, she subconsciously backed onto the dildo, igniting her fire all over again. "Ooohh... Why is it so hard to stop... Hah..."

She shook her head to clear her mind, martialling her willpower to pull herself off the dildo. She went painfully slowly, savoring the slick, velvety texture, trying her very best to ignore the yawning chasm of emptiness that invaded her mind. Rainbow shivered, her feathers fluffing up as she dove back down on the dildo. "Ok... Ok..." She panted in her momentary indecision. "T-Three more... Just three more and I'll start my workout.

She began to worry she'd just need to complete the workout with the dildo inside her. Maybe she'd keep it in her all day, just so she could clench on it to control herself when she saw those delicious, sexy, incredible vines again.

Spitfire sat in her office, trying to focus on the paperwork in front of her as she bounced up and down on her largest anal plug. The wood of the seat complained at the strain of being repeatedly impacted by her glorious ass, which apparently had grown larger and more plump overnight. If she clenched any harder on it she was worried she'd make diamonds. Spitfire had woken up with a leviathan libido, slowly tearing her mind at the seams. She'd tried ignoring it at first, knowing at this point that any further stimulation would waste precious time - time they didn't have. But trying to avoid it made her jittery and temperamental, twitching and mind aching with withdrawal, ass maddeningly empty: She couldn't have herself making any bad decisions or zoning out at a key moment. At least that's what she told herself when she caved. Hard. She'd spend most of the rest of the morning plunging her anal beads in and out of her ass, imagining what those perfect, beautiful seeds themselves must feel like.

But she couldn't allow herself to fall to the marvelous, salacious temptation of those vines... so toys would have to suffice - it would be enough. Or so she told herself. She no longer cared about going to Twilight and Zecora to seek a cure: better they didn't even know. She'd keep up this facade, using her generous salary as a Wonderbolt to cover the cost of a wild and ever-growing collection of toys, lubes and porn, which in the end, was what she really wanted out of life now, not that she’d admit it...

There was a knock on the door and Spitfire quickly straightened up and tried to make herself look presentable, shoving the butt plug as far up her ass as it would go and desperately hoping she hadn't moaned out loud in the process. She blushed deeply as she realized she felt the butt plug push up against another stiff ovoid shape somewhere far inside her. But she had no time to contemplate the implications.

"Woah Spitfire, you ok there? You look a bit flushed" Rainbow dash pointed a hoof at her, eyebrow lifted.

Spitfire blinked twice. "I-I'm fine Rainbow dash... Time to head out already?"

Soarin, Nightglider and Thunderlane entered the room and Soarin took to the air excitedly. "It sure is! Come on team; I know something like this is outside our usual weather control purview, but we've got to nip those plants in the bud!" Nightglider punctuated his quick pep talk with a burst of flame from a flamethrower she'd borrowed from Pinkie Pie. No one wanted to ask Pinkie how she'd ended up with it, but they were sure glad she had it now.

Soarin's excitement contrasted drastically with Thunderlane's glassy-eyed, thousand-yard stare.

Rainbow took note of this as well. "Woah Thunderlane; did you get any sleep last night? Are you ok to fly?"

Thunderlane shook his head to refocus. "Nah I'm good; it's not that... just... something on my mind?" Technically, it wasn't wrong. He couldn't help but run through a mental photo album of all the asses he'd seen in his life, making his cock twitch so hard. "A-anyways let's get moving; everyone's here who volunteered now, right?

Rainbow hovered as well now. "Ok team, move out! we've got to go burn down those vines before anyone else g-get's hurt!" Rainbow Dash said with a lot less conviction than she'd wanted to show. As Thunderlane turned around though, what Rainbow saw made her clench on the vibrators in her ass and pussy: the most massive bulge she'd ever beheld under a Wonderbolts costume. Her gaze unfocused as she moved to sniff his package, but then -

"WAP" Spitfire slammed down one last time on her ridiculously large anal plug, making her insides jiggle and squirm with delight. Shrewdly, she zipped up the back of her flight suit so no one would see the base of the thing, But the lewd noise had caught everyone's attention. Spitfire shrugged nervously. "Aheheh... My bad, stubbed my hoof."

Everyone resumed walking out the door; some excitedly, some with a grim determination to face this problem down, head-on.

This was a bad idea. Rainbow knew it the minute they touched down. She'd thought she could surely handle a few minutes in the presence of the vines again, but as soon as she saw their slimy, deliciously smooth, writhing surfaces, she clenched so hard she crumpled both her vibrators, only accentuating the gaping emptiness inside her. Standing in front of them was like asking a pony stranded in the desert for a week not to drink the delicious cup of cold mountain spring water before them.

Nightglider leapt into action, blasting flames around the clearing while Soarin protecting her flank, batting away vines as they intruded on their flight path. "Leedle leedle leedle lee!"

Nightglider was taken aback for a second, looking back at him incredulously. "Dafuq kinda war cry was that, Soarin?" And that was enough time for a large vine to wrap around the both of them and pull them into the dark woods, "Aaah! Spitfire, Rainbow, Thunderlane - somepony help!!"

But Spitfire and Rainbow were transfixed on the vines, and Thunderlane couldn't stop looking at Rainbow's now quite sizeable rear - now almost with enough fat to completely hide her muscle tone, her breedable hips made him absolutely ache with want. He hoped no one saw the copious trail of pre, now snaking down both his forelegs from his pulsing cocktip. He instinctively sniffed the air, groaning as his nose was caressed by Rainbow's raunchy, depraved scent - even stronger than estrus - that hinted at just how much she really wanted it. Thunderlane's cock throbbed painfully; he couldn't take one iota more. He crouched down to rub his member - if only so he didn't lose it and go mad right then and there. His eyes rolled back to the otherworldly feeling of his touch.

Rainbow's mind felt like a rope pulled taut, slowly being cut by a machete like in so many of the Daring Do books she'd read. She tried to close her eyes, but she couldn't: they were practically hypnotizing. Looking at the writhing vines was tantamount to finding an air pocket after almost drowning in a sinking ship - so enticing she felt like she needed a tentacle up her ass like she needed to breathe. Maybe even more. Maybe she'd let herself drown for one fantastic fling with an octopus...

Paralyzed by pleasure, Rainbow Dash practically drooled at the tentacles as her ass finally expanded enough to cause her flight suit to tear, ass clenching, pussy winking, sweat and marecum drenching the doomed suit. She clenched again and with a wink and a squirt, the broken vibes shot out from her ass and pussy, through the hole in her suit. Thunderlane was now masturbating furiously to the view behind her, practically frothing at the mouth, his newfound needs far exceeding the limitations of sanity, with her soon to follow. She was lost; her every thought gripped and aggressively spitroasted by tentacles, massaging her very brain with lust. She could imagine them, massaging her insides beyond nirvana. She had no idea what to do. What could she do?

Then she saw it - Spitfire had already given in, clenching her ass on a tentacle and pulling forward as if she wanted to uproot the thing, only to slam back hard to meet its thrusts. The dullness of her eyes made it clear nobody was home. At least... nobody sane anymore.

Seeing her role model over most of her childhood giving in so deeply to the depraved degeneracy - That was the straw that broke the camel's back. Rainbow's eyes stared blankly into the middle distance. She NEEDED the nearest tentacle in her ass right away, or she'd actually go insane. She'd shove it as deep in her ass as she could get it, and just keep cumming on it till she passed out, in front of the whole team if necessary.

But suddenly, just as she was about to throw herself off the precipice into depravity, deep, somewhere deep down inside herself, Rainbow Dash found one last beautiful orange ember of will. And so she hesitated, leaning dangerously over her breaking point. Would she really doom Equestria just to enslave herself to this lust for a tentacle fuck?

Her hypersensitive, aphrodisiac-laced ass clenched at the thought. Yessss - She was going to fall, but in that moment she had an idea: perhaps she could glide. Perhaps she could control the direction of her descent into madness. Buy just a little more time.

"T-Thunderlane! I want you to B-Buck my Ass!" Rainbow looked back at him with as sinful and seductive a look as she could manage, Spreading her ass cheeks and tearing her suit further, Revealing her sweating, lust-gaped ass and frenetically winking, soaked pussy. To his exponentially amped libido, there was absolutely no saying no to that offer.

Too bad Rainbow Dash hadn't realized he was also infected, but so it was: out of the frying pan and into the inferno.

"HHHRRGNH!" SHCHLRK PLAP PLAP

He mounted her and slipped right in: her new dimensions fitting his perfectly like a silky smooth glove. The tightness - her hungry twitching - the velvety smoothness - her massive squeezable asscheeks - the deep lovecraftian scent of her lust- it all blended together into a potent, insidious cocktail, blanking out his mind, making him thrust madly - just how Rainbow wanted it.

"Aaanngh... Aaanngh... BUCK YESHH..." She shouted.

Rainbow for her part was drowning in a sea of pleasure, trying desperately, but failing to keep her wits about her. She'd prepared herself for Thunderlane's dick to not be anywhere near as good as the tentacles, but she'd never in a million years thought it would be BETTER. Each stroke evoked such magnificent sensations, thrusting her deeper into the all-encompasing depravity, sending waves of synesthesia reminiscent of a rainboom through her rolled back eyes, her overloaded nervous system doing its best to comprehend just what the hell it was being put through. The rope that was her mind frayed and finally snapped, completely and utterly, as she embraced the unabashed hedonism, her cares floating away like feathers in a hurricane. These were uncharted heights of pleasure already beyond any orgasm she'd ever had - but she hadn't even come yet, though she had no idea how.

"Oh Celeshtia... This is BUCKING me UP!"

After holding back for hours flying, edging himself earlier, and now plunging himself deep in the most fantastic ass he could imagine, Thunderlane could take no more. He'd never felt more horny and backed up, like a party balloon teased sensuously by a needle. His fat nuts clenched up against his taint, his cock fully flared as he thrust it as deep as it could go, then just some slight motions to and fro, luxuriating on the absolute edge. Suddenly, one of the vines decided to plunge into his ass, caressing and thumping his prostate through the flesh, Sending him careening over the edge.

"Rainbow, I'mGUNNACUM!"

Then Rainbow clenched on him and moaned needily, signalling the start of her own orgasm. Thunderlane looked like he was having a seizure. Mindnumbing, addictive aphrodisiac cum lanced up Rainbow's ass and doused her insides, spurt after pulsating spurt turning corners in her guts like perfectly aimed pinballs, rapidly bloating her guts to what looked like the second, then the third trimester of pregnancy, then with twins, before finally traveling up her throat, dripping and splashing out of her mouth and coating her nostrils with its raunchy scent. With this stimulation, Rainbow was launched into a stratospheric orgasm the likes of which she'd never imagined, even after her experiences so far with these tentacles, full body shivers made her fattened ass jiggle deliciously as her world - her whole universe - was rocked to its core. Then, like a waning eclipse, it petered out, leaving nothing behind, the world transmuted back to normal.

Rainbow Dash collapsed on the floor, with absolutely nothing left to give: all her intense physical training couldn't keep the sleep out of her eyes. She could feel Thunderlane's erratic hart palpitations through his dick as his cosmic orgasm waned. They both ached to continue but it was all just too much. Thunderlane's heartbeat regularized again, and he pulled out and collapsed beside her, the tentacles around them almost seeming to cheer in their writhing as Spitfire still looked on with empty eyes, even further gone than them.

Rainbow woke up in the Ponyville hospital. The first thing she noticed was that her mind was back in one piece. Mostly. Her mind was no longer smothered in an insurmountable blanket of pure need, but a manageable lust more comparable to the start of estrus. Vexing, awkward, but ultimately manageable. The next thing she noticed was Soarin, sleeping next to a half eaten apple pie, and Applejack, asleep, forehooves and face plastered over the bed, wet spots near her eyes. Had she been crying?

"Aww " It brought a tear to Rainbow Dash's eye as she brought Applejack into a warm, fuzzy hug, waking her in the process.

"Rainbow! Yer back! I thought I was going to lose you!" She pulled tighter into Dash's hug.

"No dumb vines are gonna do in the awesome Rainbow Dash, silly. We'll be ok as long as we've got each other. But anyways, what happened? What'd I miss?"

Applejack took a moment to steady her breathing. "Ahem. Right. So Twilight went to find Zecora, and she didn't have a cure, but they reckoned they could team up with Meadowbrook and figure something out. Took em forever cuz they needed to get a bunch of rare ingredients from this or that mountaintop, tundra, ocean, what have you, but thank my lucky stars, it worked! Good that ya got all them vines taken care of: I doubt they'd be able to mass produce the stuff. They kept you, Spitfire an' Thunderlane sedated for upwards of a month I reckon. Oh and after all that, Coco said she didn't want it. Figures." Applejack gave the deadpan shrug Rainbow wished she could give right now, but her left wing was rather cramped after so long in bed.

"But that doesn't explain how we got out of that mess?" Rainbow cocked an eyebrow

By now, they'd woken up Soarin as well. "I can help with that Rainbow. Turns out, it was easier than we thought to scare the vines off with short bursts of fire from the flamethrower than by hoof with my sick Griffonese oil wrestling skills. I figured they'd be perfect for wrangling slimy tentacles, but I guess I was overthinking it. It was pandemonium, Night glider and I flying tandem back to back to protect our asses - literally and figuratively - through the trees with all these vines trying to grab us - I wish you could have seen it! We probably set some records for canopy flying... But anyways, eventually we finished off all the vines, and by the time we got back, you and Thunderlane were knocked out cold. We figured the vines had overpowered you, so we took you straight here. Spitfire seemed ok at first, but she ended up checking herself in also..."

Rainbow had tuned out when she got the message. They'd done it. They'd actually done it! They'd saved Equestria from that awful menace. She should be proud! ... But for some reason, deep within her, a hungry emptiness lingered.

Next door, Spitfire sighed in contentment. Her withdrawal from the vines had her a little antsy, sure, but she'd be fine. Yes she'd be fine - because before she'd checked in at the hospital to have herself cleaned out, she'd layed the first few seeds in her apartment. The anal beads hadn't held a candle to it - It was SO perfect: she'd cum her brains out with each and every seed, passed out in her own juices, and when she awoke she'd been tempted mightily to just keep repeating the process until someone showed up to check on her, but she miraculously still had the presence of mind to know that if that happened, she'd never get more of that feeling again. And so she hatched her plan, along with her new vine plants. No one would suspect a thing. She had enough self control not to spread the terrors further afield... maybe. She couldn't bring herself to care about that too much anymore though. Soon - very soon - she'd be discharged with a clean bill of health. And to celebrate - as soon as she got home - she'd sink herself straight back into utter depravity.

Author's Note

Inspired by 2914031 and 2922885 on Derpibooru and Slimewiz's twitter status 1557525948995706881

I take it back: Appledash love triangle with tentacles is best ship dynamic