Sexy Brain Parasite Story

by Damaged


Dogged Determination

"Wh-Who was that? He seemed very…" Looking back to the living room, Fluttershy finally noticed the grooming items, as well as the empty (of fresh strips) box of body wax. "Wh-Where's Thunderbolt?"

"Oh, he is outside. He normally runs around out there most of the day." Rainbow Dash pulled her wing and arm back awkwardly, and led the way through the house—the things in the living room could just stay there for now. "Hey! Thunder!"

Outside, Thunderbolt was strutting back into his own yard. He had needs now, stronger ones than ever before in his life, and it hadn't taken much to jockey the local bitches into helping him slake them. He barely got his head through the doggy door when he saw—and heard—his owner calling his name.

It was so good to be welcome again. He had worked out what his owner had been upset about—it was hard not to when she immediately covered his marking with an overpowering one of her own—and he had to respect a bitch who would stand up to him. Their casual night couplings were still fun, and he appreciated her more for them—even if he wished she would be more free with herself.

"Hello Thunderbolt." Fluttershy crouched down and held her hand out. The big shepherd rushed over to Rainbow Dash first, however, and only once he had touched his owner's fingers with his nose did he turn to Fluttershy. It only took a small yowl for him to get his message across, and Fluttershy blushed hotly.

"What did he say?" Rainbow looked between Thunderbolt and Fluttershy.

"He…" Fluttershy stood up quickly, straightening her back as she realized how exposed it could leave her. "He pr-propositioned me." The words came out in a squeak. "I-I already have someone, Thunderbolt, sorry."

Thunderbolt's excitement cooled a little, and he returned to his owner's side, happy to nuzzle her hands and get a good petting. Still, his eyes traced over to Fluttershy, and a hunger built in him. Despite having serviced three bitches that day already, Thunderbolt started to slide from his sheath.

"Well." Rainbow Dash looked to her friend. "Can you ask him?"

Awkward was not an ample enough word to describe the situation. It had seemed to simple to Fluttershy when she had come up with it, just ask Thunderbolt, then point out that she needed to stay and make sure it was okay, then… Fluttershy didn't have enough willpower to think about "then" and stand upright. She closed her eyes, built her courage, and let the words come. "Thunderbolt, would you feel comfortable in a sexual relationship with Rainbow Dash, your owner?"

Feeling aroused again, Rainbow Dash tried to look anywhere but at Fluttershy, and instead focused on Thunderbolt's excitement. To her surprise he barked and bounced a bit, then looked up at Rainbow.

"He—He said… He said he wants to take you as his—his bitch." Fluttershy had to say the words, had to use the language Thunderbolt had. "Rainbow Dash, I think he is very okay with—"

"Fluttershy, I need to ask you something that might be really strange, really freaky, and I totally understand if you run away and don't talk to me for a week." Rainbow Dash looked down into Thunderbolt's eyes, and for a few seconds they were both in complete understanding of what the other wanted. "Can you stay and keep an eye on us, make sure he doesn't hurt me, or get hurt by me?"

When a brain got handed exactly what it wanted on a silver platter, it sometimes had trouble accepting it. Fluttershy stared at Rainbow Dash for a few seconds, then slowly started to nod her head. "Y-Yes, of course. I should—I should make sure nothing bad happens." With each word, Fluttershy's smile grew wider and wider.

"You're totally a lifesaver!" With all said, Rainbow Dash backed out into the hall, and started walking for her bedroom. She heard Thunderbolt's paws scrabble on the tiles in the laundry before meeting the carpet—he was following her.

Thunderbolt had taken store of the situation and realized what had happened. This was all an elaborate game that he had to play along with to be able to take his owner. With a perky trot, he followed her down the hall and into her bedroom. Humans could be so complicated sometimes, was Thunderbolt's doggy-thought.

Realizing she was going to be left behind, Fluttershy gave a tiny gasp and followed after, making a little procession towards Rainbow Dash's bedroom. She followed Thunderbolt into the room, and saw Rainbow already pulling her shirt over her head. "Oh! Um… You're going to—to right now?"

"That was the plan, right?" Rainbow Dash turned to stand in profile to Fluttershy's view. "Was there anything else I should know? What is he going to want to do? Should I do anything special to relax?" She took a deep breath and unclipped her bra. "Because if there is, I don't think I would have a hope of doing it."

"N-No. He should have an idea of what he wants to do with you. He-He will let you know what he wants to do." Barely able to hold herself still, Fluttershy imagined her lithe friend on all fours, and had to cross her legs. While she watched, Thunderbolt stuck his nose into the discarded bra's cups one after another.

"Cool. I kinda like to be pushed around and shoved a bit. He won't bite, will he?" Rainbow Dash slipped her pants down, catching her underwear too and revealing herself—apart from her collar and wrist cuffs. "So I guess this is it."

A little growl caught Fluttershy's ears, and she turned her attention to Thunderbolt. "He… He is going to—" Her words cut out as Thunderbolt strode forward and shoved his snout against Rainbow Dash's vulva. Fluttershy's own gasp of shock was covered by Rainbow Dash's.

Normally Rainbow Dash would push Thunderbolt aside, particularly if one of her friends were watching, but instead a feeling of resignation sank over her; she was there for him to use, after all. Spreading her feet a little further apart, she let out a second whine as his tongue pushed between her lips.

Thunderbolt had eaten his owner out before, it wasn't anything new, but what was new was her reaction: her body language spoke to his needs, and his desire. He pushed his tongue as deep as he could, probed for her essence, and drank it down. At last he backed up and barked.

Rainbow Dash stared at Thunderbolt, then started to look at Fluttershy for a translation.

"He said, 'On the floor, b-bitch.'" Fluttershy's heart beat hard in her chest. She could only repeat the words because they weren't hers, and they weren't for her. She watched, and when Thunderbolt barked again, she cleared her throat. "He said it again."

"Y-Yes…" Rainbow Dash, adrenaline pumping through her system in anticipation, her body preparing to "fight or flight" as it were, turned around and started to lower herself. Settling down to one knee, she began to bring the other leg down when Thunderbolt hit her from behind. "Hey!"

Catching herself on her hands, Rainbow Dash felt the heavy mass of her pet land atop her. Everything was becoming very real, very now. She started to shift, to move, when a nip came at her shoulder. Then another. She froze in place, not wanting to be nipped more seriously.

Finding his owner a little more jittery than normal, Thunderbolt gave her a few pointers in the form of his canines. The nips weren't hard—he knew her skin was easier to break than another dog's—but they had the desired effect when his new bitch froze.

Eyes wide, Fluttershy moved closer, watching as Thunderbolt adjusted himself, pulling further up Rainbow Dash's back. "R-Rainbow Dash, are—are you alright with this still?"

Rainbow, her mind slipping into subservience to her present master, turned her face up to her friend and gave a weak nod. She opened her mouth to tell Fluttershy that she was alright, that she was just really into what was happening, when Thunderbolt shoved into her.

He wasn't a gentle and calm lover, not even a caring and playful dominant; Thunderbolt was a dog, and Rainbow Dash was his bitch. He shoved hard into her, and his hips seemed to become a jackhammer. She had to brace her hands against the floor, had to dig her fingers into the carpet to hold back for him.

With each thrust, Rainbow felt a sharp return of the pressure the toy had inflicted on her the previous night, but slowly, a little more with each bestial thud against her rear, the awkward feeling turned to pleasure.

"Oh my gosh…" Fluttershy's hand had migrated down to her dress, lifted the front, and charged down the front of her fresh panties. She started rubbing, uncontrollably, watching as Thunderbolt slammed himself into Rainbow Dash over and over.

For Fluttershy, it wouldn't have been better if it had been her under, or even atop Rainbow Dash, there was just something about seeing her friend taken like this that had her shoving two fingers into her soaking folds, while another hand sought her phone.

Rainbow Dash, her head down, watched the carpet jolt forwards and back. Each thrust into her drew a grunt of pleasure, and each withdrawal a whine of need. The actions came so quickly she was left making a moaning sound that sang in her own, pointed ears.

Thunderbolt had no control over his body once a bitch was under and around him. His body was a machine built for fucking, and fucking it was good at. But there was an odd sensation coming from his bitch, power, magic.

Fluttershy's own wings fluffed up behind her, and her hair grew up into a cascading mane of hair. She gasped in pleasure, worked an extra finger into her body, and groped under her top at her breasts. "F-Fuck her!"

Magic made everything better, or so Rainbow Dash's new mantra in life went. Sex was no exception. She felt the magic, the power, and still remained in utter surrender to Thunderbolt. Something new was happening with each thrust, something she had only read about. Each time he shoved himself back into her smaller body, she felt a shape growing a little bigger, and felt his shaft grow a little bigger too.

When Thunderbolt's knot sank into her for the last time, and didn't pull back out, Rainbow Dash climaxed. Magic poured through her, and her ears folded back as another cry rose to match Rainbow's.

Her whole body was on fire. It felt like every nerve from her toes all the way to the tips of her ears was afire with pleasure, and for all Fluttershy knew they were. With Rainbow Dash on her hands and knees, rocking under her pet, Fluttershy's lust knew no bounds. "T-Take it! Fuck her!"

The ride wasn't over, not by a long shot. Thunderbolt knew his bitch was in the midst of her peak, he had taken her often enough to judge it, but he still had his own pleasure to deliver. Fighting the tie that bound them, he kept humping forward for all he was worth.

Rainbow Dash's arms gave out, and her upper body slumped to the floor. Open mouthed and drooling, she felt the fully-swollen shaft of Thunderbolt inside her start to twitch and jolt around on its own. Suddenly, a hot rush of fluid-warmth swelled, and she knew heaven for a second time.

Thunderbolt slumped onto his bitch, and she was his bitch. All the times he had taken her, his bitch had been passive, merely accepting. This time, when his bitch had offered herself, Thunderbolt could really feel it was her surrender to him. It made him want to—want to lift up his head and roar!

The sound, somewhat like a movie would have you believe a monster makes, shook through Rainbow Dash. A strong heat radiated into her all along her back. Thunderbolt's every movement translated through the swollen penis inside her, and she loved every second of it.

Fluttershy stared at the dog. Thunderbolt was still in his dominant—as all dogs were when mounted on/in a bitch—stance, but something was different. The scream he had made, a challenge to all that Rainbow Dash belonged to him, made her really look at him. She saw something very strange.

Atop Thunderbolt's head, a pair of little horns had sprouted, and all down his spine a series of spikes emerged. His snout looked a little different, with what seemed like bare skin starting midway towards the nose actually being a fine coat of scales. When he turned to look at Fluttershy, and opened his mouth, Thunderbolt revealed a much sharper set of teeth than any dog had ever possessed.

"Oh my!" Fluttershy took a step back, her hand sliding out from under her dress. "Th-Thunderbolt, what happened?"

Tugging at the join between them made Rainbow Dash's eyes snap open. She whined like the bitch she felt as Thunderbolt moved around. No longer possessing the strength to beg her master to stop, she just kept the soft whimpering up.

When the movement stopped, Rainbow made a happy sigh, and when Thunderbolt licked up her cheek, she made a more appreciative one. Only the tongue that lapped along the side of her face was not shaped quite as a dog's should be.

Both girls and Thunderbolt were content to relax. The peak of their excitement had been and passed, and though Thunderbolt kept spraying his seed into Rainbow Dash in short, wild jets, he was mostly done.

In Rainbow Dash's head, her parasite was very content with its host. She had finally given herself willingly to her mate, and the performance had provided both sets of parasites with plenty of food. It washed her mind in happy chemicals, making sure she knew this was the proper behavior.

Thunderbolt's mind was a little more chaotic. Something major had happened, and the parasite that had been mature now found itself with a lot more to work with. More advanced thoughts rattled around Thunderbolt's head, and it left both host and parasite reeling with possibility.

The first order of business for Thunderbolt, however, was to thank his bitch. Licking along the side of her face, his long tongue stroked from the tip of her chin all the way up to her temple. Their bodies were still locked together, and though Thunderbolt might turn around on any other bitch, this one was his bitch, and his alone.

"R-Rainbow Dash?" Fluttershy had folded to her knees on the floor, and was almost shocked by the size of Thunderbolt above her. The dog now bore some strange changes, ones Fluttershy was confused as to their origin.

"Mmm…" Sprawled on the floor, her lover still above and inside her, Rainbow Dash was floating on cloud nine. She turned her head towards the questioning voice, not realizing what was going on until she finally opened her eyes and looked at Fluttershy.

Fluttershy was ponied up. She had the typical pony ears, and her hair was pulled up into a mane. Rainbow had no reason to believe her friend didn't also have a tail. Something was a little odd about Fluttershy; she looked flush. "Are you alright, Fluttershy?"

"Y-Y-Yes." Fluttershy shook herself, and her wings ruffled at her sides. Her more intense ponied-up form was like the regular one, but more of everything. "I don't know what, but I think something has happened to Thunderbolt. Remember when we ponied up, and vice-principal Luna did too?" Rainbow Dash's suddenly wide eyes stared at Fluttershy, and Rainbow nodded. "I think he is becoming some kind of snake, or—or maybe like what happened to Sunset."

The news that something had happened to her pet broke the spell of submission, and Rainbow Dash tried to get up, to make sure Thunderbolt was okay. That she was still locked on his shaft, and pinned under his weight, made that seem impossible. Gritting her teeth, Rainbow Dash lifted one leg forward and turned to the side.

The strain of that huge shape turning inside her almost caused Rainbow Dash to black out, but concern for her pet galvanized her into action. When she looked up at him, Thunderbolt leaned down and licked her directly on the face. "Ack! Enough!" She couldn't stop a laugh from spilling out. Tied to him didn't stop a face-bath from being funny. "Stop, boy, please?"

"Wow." Rainbow Dash stared up at Thunderbolt's face, his nose only inches from her own. "You look—awesome." She tried to twist a little more, and fell over and landed on her back. Able to stare up at Thunderbolt much easier, she noticed all the little things. The scales along his snout were a shimmering green. The horns on his head seemed bright yellow. "He doesn't have any fan—" She didn't get any further; Thunderbolt lay down on her chest.

Fluttershy reached into her handbag and pulled out her mobile. "C-Can I just take some photos? Just so I can try to match his—his reptile bits?" Of course she planned more uses for the photos than that; this might be her one and only time of catching this happening in the flesh.

"Sure." Being photographed while pinned under her dog actually made Rainbow Dash feel a little more excited. "Do you need some of his and my… uh…" She wiggled her hips.

Eyes wide, Fluttershy could only nod her head and start taking photos. Her phone clicked again and again and, by the time she had circled the couple and taken what she wanted, she had nearly two hundred pictures.

Thunderbolt knew how long he normally lasted in a bitch, and though Rainbow Dash was a very good bitch, he judged it time to break the tie. Standing up, he felt a slight tug at his shaft before it suddenly gave way. His knot had shrunk enough, and he was free of his bitch. In the past he would have found somewhere to lick himself clean, but new ideas blossomed, and rather than retreat to his doggy bed, he sat down before his bitch, positioned so that his shaft was inches from her face.

The demand was clear. Rainbow Dash could smell hot, excited dog, and she could smell herself. Rolling back to her belly, she crawled forward and wrapped her lips around Thunderbolt's member. Rich and musky, the taste rolled over Rainbow Dash's tongue as she sucked and cleaned Thunderbolt off. Though she wished she could, his length was too much for her, and she had to pull back and simply lick the last of him clean.

A camera flash startled Rainbow Dash. She froze, turned, and then looked at Fluttershy. "Uh…" She eyed her friend, noticed that while one of Fluttershy's hands held her phone, the other was under the girl's skirt. "Did you get a good angle?"

The question, and the situation, was more than Fluttershy could handle. She started to shake a little, and grabbed at her handbag. Run run run! Only Bridget could turn Fluttershy's "flight or fight" response to the latter, which left her with trying to get away from the situation.

Fluttershy got all the way to the kitchen before a hand closed on her shoulder. "I-I-I didn't m-mean to!" She turned, and saw a grinning, naked Rainbow Dash holding her by the upper arm.

"You didn't mean to masturbate and take a photo of me sucking on Thunderbolt's dick?" Rainbow Dash lamented a few things, chief of which right now was the feeling of something slimy sliding down her legs. Her eyes widened. "I need your help, Fluttershy. Please?" She crossed her legs, hoping she wouldn't make a mess on the carpet.

Cutting through her terror like a knife, the fact that a friend needed her was suddenly more important than Fluttershy's embarrassment. The hand on her arm weakened and then released, and when Rainbow Dash—cupping her crotch and squealing—ran back down the hall, Fluttershy followed.

Rounding the corner of the bathroom, Fluttershy poked her head in to see Rainbow sitting on the toilet. Her friend had always seemed so strong, so powerful. Whenever any bully had threatened, Rainbow Dash had always stepped up, no matter who was being bullied. Fluttershy's mind raced, and she noticed dozens of little details: the mess on Rainbow's legs, the panicked look on her friend's face. Stepping into the bathroom, Fluttershy reached for the washcloth at the sink and soaked it with water.

"That was amazing." Fluttershy couldn't believe she had said it. She wanted to say more, but she couldn't. Instead, Fluttershy crouched down and started cleaning up Rainbow Dash's legs.

Jerked from her minor panic, Rainbow Dash felt the cloth work up the inside of her legs—one, then the other—and her eyes met Fluttershy's. "Yeah. He was—he was everything I thought he would be." She felt the mess leaking from her body, and tried not to think about it too much. "I am glad you were there."

"Me?" Fluttershy looked up. Her eyes met Rainbow Dash's, and they shared a moment of understanding. "Y-You needed someone to watch."

"And you liked watching." It was obvious, now Rainbow Dash looked back at everything. The actual sex occluded everything but the sensations, but after that she remembered how excited Fluttershy looked. "It's okay. I liked that you were watching. C-Can you send me the photos?"

Fluttershy didn't realize how far she was going with her cleaning. She was so focused on Rainbow Dash's words that her cloth traced Rainbow's thighs all the way up to her crotch. Her instinct to squeal and jerk back was undone by Rainbow Dash widening her thighs a little. Tentatively, she went back to cleaning, telling herself that it was just like cleaning off an animal.

"Is Bridget in your camper still?" Rainbow Dash leaned back on the toilet, watching Fluttershy clean her. Something had changed in the way Fluttershy was performing the task: tentative touches had turned to sure ones.

"Oh my goodness, she is!" Fluttershy jerked up to her feet. "I really should go, she might be eating… everything." With quick, economical strokes, Fluttershy finished cleaning the mess from Rainbow Dash's legs.

Thunderbolt was done with his relaxation. He stood up and walked to the cleaning room. Fluttershy raced from the room, down the hall, and was gone. He looked in to see his bitch sitting on the drinking fountain. Something was odd, though. She was his bitch, but that didn't seem quite the same thing as what it had earlier the same day.

His claws clinked on the tiled floor as Thunderbolt walked into the room. Making his way over to where Rainbow Dash sat, he leaned his weight against the nearby bathtub, sat down and set his jaw on Rainbow's lap.

Smiling down to Thunderbolt, Rainbow Dash's hand reached out to one of the ear-ridges and began to rub. "You seem more mellow." Rainbow Dash heard a soft, contented rumble come from Thunderbolt—almost like a purr. "Did you find a good bitch to pound?"