Author's Notes:

I couldn't resist doing one for her now I know fetish stories are actually a thing for her, plus I've taken to heart comments that I should write what I want and have fun with it, whatever anyone else thinks. Besides, aside from 13 anonymous dislikes, the reception to this story has generally been positive.

Also, this will try to be less repetitive from Pinkie Pie and Rarity. And I know Fluttershy would never do this in the show. I also wanted to depict someone besides Applejack with the fetishes.

Rainbow Dash and Fluttershy were on their way back to Fluttershy's cottage after flying an aerial race against Spitfire and Soarin, which the two Wonderbolts had won. Both pegasi were wearing their Equestria Games outfits - yellow tank top and skintight white shorts, which were now very damp with sweat.

As they landed at the door of Fluttershy's cottage, Fluttershy said "I'm sorry we lost, Rainbow Dash."

"That's all right," said Rainbow Dash. "It was still a fun race."

They walked inside, where Rainbow Dash had brought over several water bottles for after they were done the race. They began drinking from them. Rainbow thought the water tasted funny, but Fluttershy didn't notice, as she was more thirsty than Rainbow Dash. Then, as Rainbow Dash drank her fifth water bottle, she remembered - she had put fart powder in these water bottles, intending to drink it both for her own amusement, and for her next session with Applejack, Pinkie Pie, and Rarity. Rainbow stopped drinking after the fifth bottle, while Fluttershy drank 10 bottles. Rainbow wasn't sure whether she should tell her or not. She knew Fluttershy wouldn't like it, but she still thought it was funny.

Within minutes, Fluttershy was feeling very uncomfortable. Hoping that Rainbow Dash didn't notice, Fluttershy let out a quiet, airy fart. The relief felt good, but she blushed, having farted in front of Rainbow Dash.

Rainbow Dash noticed the expression on Fluttershy's face and knew what she had done. She tried hard not to laugh. Fluttershy felt more embarrassed, and accidentally farted louder than before. Rainbow Dash fell on her back and started laughing harder.

"Um, excuse me," said Fluttershy, blushing beet red.

Rainbow stopped laughing, not wanting Fluttershy to feel too bad. "Don't feel ashamed, Fluttershy," she said. "I think it's cute and funny when you fart."

"You really mean that?" said Fluttershy, blushing more from something besides shame.

"Of course I do," said Rainbow Dash. She farted loudly and chuckled.

Fluttershy began to relax, and let out a loud fart that lasted seven seconds. She was still blushing, but giggled a bit, while Rainbow Dash laughed harder, accidentally farting a few times which made her laugh even harder.

"Rainbow Dash, can I ask you something?" said Fluttershy, releasing a silent fart that Rainbow didn't notice. Rainbow nodded. "Pinkie Pie told me what she, you, and Applejack like to do sometimes."

She hadn't mentioned Rarity. It seemed as though the fast-talking mare had kept her word.

"And, I was wondering... could you maybe rub my rear?" She blushed a little. "I've always wanted you to do that."

"Sure," said Rainbow Dash, her heart pounding. She had always wanted to do this to Fluttershy but had been sure Fluttershy would never want her to.

Fluttershy turned around so her tush was facing Rainbow Dash. Rainbow put both her hooves on Fluttershy's butt and started rubbing. Her butt was as soft as Rarity's, and she loved it! Fluttershy also took great pleasure in this. Then, she accidentally farted in Rainbow Dash's face, and blushed. But Rainbow Dash giggled, and Fluttershy relaxed, knowing Rainbow didn't mind. Fluttershy farted again, this time intentionally, giggling a bit.

After a while, Fluttershy said "Now, Rainbow Dash, can you... slap my rear?"

"What?" said Rainbow Dash.

"I want you to slap my rear ten times," Fluttershy said, blushing a little. "As hard as you can."

"I can slap pretty hard," said Rainbow Dash, but she didn't argue much. This was what Fluttershy wanted. Rainbow Dash slapped Fluttershy's butt with her hoof, causing her to squeal. "Was that too hard?"

"No, it was just right," said Fluttershy. "Now, nine more times."

Rainbow Dash spanked Fluttershy again, and again. Fluttershy felt pain explode through her rear, but loved every second of it.

After Rainbow swatted Fluttershy the tenth time, she turned around. "Now do the same thing to me," she said.

Fluttershy raised her hoof... and patted Rainbow's behind lightly.

"Come on, you can do better than that!" said Rainbow Dash. "Slap as hard as you can!"

"If you say so," said Fluttershy. She raised her hoof and slapped Rainbow's butt surprisingly hard.

"That was awesome! Keep going!"

Fluttershy swatted Rainbow's tush nine more times, Rainbow Dash greatly enjoying each one. Her butt hurt when it was over, but she didn't mind.

"We should do this again sometime," said Rainbow Dash. "Of course, you'd probably prefer if it was just us and not Pinkie Pie and Applejack." She didn't mention Rarity either, also having promised never to tell that she was involved in their fetish activities.

"If it's all right... can I ask one more thing of you?" said Fluttershy. Her heart was racing; she had never asked this of anyone else before, but she had just had Rainbow Dash rub and slap her butt, and done the same to her, and was no longer able to feel shame farting in front of her, plus Pinkie had said Rainbow thought it was fun to wet herself, so she was sure to accept this.

"Anything you want," said Rainbow Dash.

Fluttershy whispered something into her ear. Rainbow couldn't believe what she was hearing. Fluttershy's fetishes ran deeper than she could have imagined, maybe even deeper than Applejack's. But it would be just as fun for her as it must be for Fluttershy, so, trying to act cool, she said "Yeah, I can do that."

"So, until then..." said Fluttershy, turning around so that Rainbow Dash could continue rubbing her butt with her hooves.

About an hour later, Fluttershy had to pee badly. All the water bottles she drank were affecting her. "I need to use the little filly's room," she said, and ran toward the bathroom.

Rainbow Dash zipped over in front of her to block her path, facing away from her. "I won't let you," said Rainbow Dash.

Fluttershy pressed her head against Rainbow's butt and tried to push her out of the way. "Please, I really need to go."

Rainbow Dash responded by sitting on Fluttershy's head. Rainbow's butt was still sweaty, but she was able to breathe. She tried pulling her head out, to no avail.

The pressure in her bladder grew stronger and stronger. She knew she couldn't hold it long once she needed to go this bad. She remembered the time she had worn one of Rarity's skintight white outfits as part of her fashion show, but had forgotten to use the bathroom before. The show didn't last long so she had raced home, but she didn't make it. Rarity was upset that Fluttershy had peed in one of her outfits, but she didn't give her a hard time because she knew it was the last thing she needed.

Then Rainbow Dash farted loudly. It smelled awful, and Fluttershy kept trying to pull her head out from under Rainbow Dash's butt, but still couldn't. Her behind was in the air, and she also let out a loud fart, to which Rainbow Dash chuckled.

Fluttershy was in desperate need of a bathroom and she knew she couldn't hold it much longer. Then, Rainbow Dash farted on her again, which lasted five seconds. This was too much for Fluttershy, and she felt her shorts grow warm and wet as she began wetting herself. She could feel waterfalls of pee flowing down her legs and forming a puddle at her back hooves.

Rainbow heard the sound of Fluttershy peeing. She felt so aroused by this, she had to take a quick peek. She started to lift her butt off Fluttershy's head.

"No, not yet!" said Fluttershy. Rainbow sighed and sat back down on Fluttershy's head.

Fluttershy had never thought she would do this before, but she loved every moment of it. The warm release, the feeling of the pee flowing down her legs as her skintight shorts grew wetter and wetter, and the naughty feeling of doing something like this and playing out her fetishes. When she had wet herself after Rarity's fashion show, despite being embarrassed at Rarity finding out, she had secretly enjoyed it. While she would sometimes pee in her Equestria Games outfit when no one else was around, and wash it to hide this from anyone, she had always wanted to try it combined with another mare sitting on her head, having seen Pinkie do this to Rainbow once. Rainbow Dash was the perfect pony to satisfy this for her.

Once Fluttershy finished peeing, Rainbow Dash stood up and turned around. Fluttershy was blushing lightly, but looked satisfied all the same. Her shorts were soaked with urine, and she smelled of it too, along with a bit of sweat and farts. In that moment, Rainbow Dash peed herself, even though she didn't have to go that bad. Both she and Fluttershy really enjoyed this so why shouldn't she do it in front of her? She sighed in immense satisfaction as she soaked her skintight shorts.

As she finished wetting herself, Rainbow Dash said "How was that? Was the farting too much?"

"No, it was perfect," said Fluttershy. "It's actually fun when you fart on my head." She blushed lightly.

"We'll have to do this again," said Rainbow Dash. "Maybe we could switch places sometime."

"I can't wait," said Fluttershy. "But... let's not involve any of the other ponies. Let's keep this between the two of us."

"Don't worry," said Rainbow Dash. "I'd never do that to you."