Author's Notes:

This chapter contains a bath scene.

The next morning, the girls awoke. Rainbow Dash and Rarity walked upstairs to Rarity's bedroom, Rarity still wearing her pajamas.

"Here's your dress," said Rarity, holding out her light blue shirt and purple skirt. "And a pair of underwear and socks. I have a full set more of them in this bag. Now, go into the bathroom, shower thoroughly, and come back out wearing my clean outfit."

Rainbow Dash did so. It took about twenty minutes but she emerged from the bathroom, looking and smelling very clean, wearing Rarity's dress, and carrying her own outfit in her hands.

"Now change into this and DON'T shower," said Rainbow, keeping the skirt while handing her shirt, jacket, skintight shorts, socks, and underwear to Rarity.

Rarity took the outfit, wincing slightly at how dirty it felt, and walked into the bathroom, locking the door. She sniffed the outfit and recoiled. It smelled absolutely foul. Like a combination of weeks' worth of sweat and farts, with a hint of pig breath. But, she had taken this dare. She changed out of her pajamas, and exited the bathroom in Rainbow's smelly outfit, minus her skirt. The white shirt was dirty enough to not look camouflaged against her.

"How can you stand wearing this all the time?" said Rarity.

"I'm used to my own smell," said Rainbow. "And now, our bet begins!"

"If I may," said Sunset, "maybe limit it to two weeks? If neither of you has lost by then, it'll prove you're willing to do that for a long time, and we can call it a tie, with neither of you having to lose."

"Sure," said Rainbow Dash.

"I suppose," said Rarity.

...

Rarity made her list of foods that would make Rainbow Dash fart more than usual, and showed it to her. Then she made toast for everyone.

Pinkie handed her a shaker of fart powder. "This should last the two weeks! Don't use too much at once."

Rarity shook it once above her toast, causing a small amount of the powder to fall on.

Once they'd all finished eating, Rarity felt gassier than she ever had in her life.

"I... need to use the ladies' room," said Rarity. Rainbow looked at her. "I mean..." She hesitated, then lifted her leg.

FFFFFFFRRRRRRRRRRT!

Rarity blushed beet red, extremely embarrassed that she had just farted loudly in front of all her friends. Rainbow Dash and Pinkie Pie laughed.

"Rarity, I hadn't taken my morning pee yet," complained Pinkie when she stopped laughing. "Before now, that is."

"I am dreadfully sorry, Pinkie Pie. That was so unladylike of me."

"Get used to it, Rares," said Rainbow Dash. She could feel a fart coming, which felt smaller than her usual farts. She lifted her leg, but remembered her bet, so she held it in until she was on her way home with her supplies, and then she farted silently. She was surprised that she was capable of such a thing.

...

Rainbow Dash was running a race today. Rarity had finished the dresses she was working on by then, so she entered the race beside her. Rainbow was now wearing a light blue tank top and short, skintight, purple shorts.

"Now remember," said Rarity. "Shower after this race." She lifted her leg and released a silent fart.

Rainbow sniffed. "You have to fart louder than that!"

Rarity closed her eyes and let out a much louder fart. The other racers looked at her. Rarity blushed, and Rainbow Dash laughed.

Once they had run their race, which Rainbow Dash won, both she and Rarity were sweating profusely in the summer heat.

"I need a good shower," said Rarity. "I mean... you do, Dashie."

Rarity accompanied Rainbow Dash to her house, where Rainbow stripped down to her black bra and panties so she could shower. Rarity knew Twilight had already set up the camera, but she wanted to make sure Rainbow could do it.

"Oh, and you are NOT to relieve yourself in the shower," said Rarity.

"Then, can you leave the room for a minute?" said Rainbow Dash.

Rarity did as she was told, and once the toilet flushed, Rainbow opened the door and let Rarity in as she turned the shower on and climbed in. She washed herself thoroughly with soap, also using shampoo as she usually did now, and then rinsed herself off.

"Splendid," said Rarity.

Once Rainbow exited the shower, she dried off and changed into a purple pair of underwear, with Rarity out of the room. Then she put Rarity's dress back on.

"And... I can't shower," Rarity griped.

"Hey, I should wash my bed sheets. They probably smell pretty bad too. Maybe now would be a good time to teach me how to work the washing machine."

"Right away. It's pretty easy."

...

The following day, Rainbow Dash got out of bed. She was momentarily surprised to see she was wearing Rarity's very clean pajamas. She got out of bed, and was about to go to the kitchen to make breakfast, when she stopped. She grabbed Rarity's dress, new socks, and a change of underwear, walked into the bathroom, and turned the shower on.

Rarity also got up in her own bedroom. She sniffed her armpit and winced at the smell, though it wasn't really bad yet, except for the outfit she was wearing. She got out of bed, and walked straight into the bathroom. As she brushed her teeth, she thought of how she needed a shower. She had just put her hand on the shower tap when she remembered. She let go of the tap and got out her bottle of dry shampoo. She paused to fart loudly.

...

That evening, once they'd done everything they had scheduled for today, they had dinner at Rarity's house. Rarity cooked the same thing for them both, but, remembering their bet, she sprinkled fart powder on her plate. She winced at this because the effects of the beans she had for lunch had just started to wear off.

"That's right, Rarity," said Rainbow.

Rarity sat down with their plates, and they began eating. Rainbow ate more gracefully than she usually did. Rarity did the same, looking at Rainbow Dash nervously, but Rainbow didn't make any comment, so she assumed this was all right.

"Are you having second thoughts yet?" said Rarity.

"It is a lot to remember, and I'm not used to it, but, I think I can last the two weeks. What about you?"

"I smell rather unpleasant right now, but I'm not about to give up either."

PPPBBBBLLLLTT!

"You gotta admit," said Rainbow Dash, "it feels pretty good to not have to hold it in all the time."

Rarity hated to admit it to herself, but Rainbow Dash was right.

...

On Day 3, Rainbow Dash played a soccer game, showered, and met Cherry Fizzy for lunch at a restaurant.

"Rainbow Dash, why are you dressed like Rarity?" He sniffed. "And what happened to your smell?"

"Rarity and I have a bet," Rainbow explained. "She thinks she can be grungy longer than I can be clean."

"Well, you were willing to try being clean for me, so you have a chance. How much are you betting?"

"If I lose, she'll give me a bath in front of everyone, and make me wear a frou frou dress for the rest of the day."

Cherry giggled. "That would be kind of funny."

"I hope you don't mind the... non-smell."

"Smell or no, I still like you." He kissed her lightly on the cheek. "Besides, I don't think Rarity will last very long. Does the bet involve her farting a lot?"

"Oh yeah. But she might be tougher than I thought. Maybe I gave her too big a motivation by saying she had to pee in one of her dresses and wear it for the rest of the day if she lost."

...

Rarity, meanwhile, was selling some dresses, having been unable to attend Rainbow's soccer game today. She was starting to smell, but she sprayed air freshener in the boutique so no one could smell her. This wasn't against the rules of their bet. She still tried not to get too close when selling her dresses.

"Why are you dressed like Rainbow Dash?" Sweetie Drops said as she paid for a dress.

"Because... I'm working on a new line of sports outfits, and I started with Rainbow's outfit." Rarity laughed nervously.

"Ooh, I'm looking forward to seeing it finished." Sweetie Drops left the shop.

Of course she had only said that to hide what she was doing from her customer, but she thought, maybe it was time to expand her boutique from dresses to sportswear as well.

She waited until no one else was in the room to fart as loud as possible. The air freshener took care of the smell. She knew none of her friends could hear it, but she was determined to win the bet. She considered farting in front of her customers, but dismissed the idea. After all, there were times when Rainbow Dash wouldn't fart. So, Rarity would only fart when she was alone or around her friends.

...

For days, Rainbow and Rarity kept to their new positions. Rainbow showered every morning and after every sports activity, and Rarity didn't shower at all, only washing her hands and hair. Rainbow would occasionally sniff her skirt, and be surprised to notice a smell more easily.

Exactly a week into the dare, the girls all met at a restaurant for lunch, in which Rainbow said she'd pay the bill. Rarity sprayed the area with air freshener, for she smelled nearly as bad as Rainbow's outfit by now.

"Well, I've got two bits of good news," said Sunset after they ordered their food (Rarity ordering beans). "Well, three if you count not being gassy at this moment."

"Ooh, what is it?" said Rarity.

"The first is that the princesses of Equestria managed to close the breach between worlds. It was torn in the fabric of space by their fight with two powerful foes: A centaur named Tirek, and a draconequus named Discord."

"Dracone-what?" said Pinkie Pie.

"An all-powerful creature with a body made up of all sorts of animal parts," Sunset explained quickly. "Fluttershy, your pony self was able to reform Discord, and the princesses locked Tirek in Tartarus."

"Tartarus?" repeated Fluttershy.

"Equestrian prison. It's guarded by a giant three-headed dog. So, the magic won't be coming through to cause any more anomalies in your world."

"Is the other portal still open?" said Twilight.

"The one humans and ponies can go through? Yes. I was just there when they told me."

"So, you're going away?" said Fluttershy.

"I will miss you terribly," said Rarity.

It meant a lot to Sunset for Rarity to say this when someone as ladylike as her would be expected to be disgusted at someone who farted so much. "Actually, no. My only real friend there is Princess Twilight. That is, your pony self," she pointed to Twilight. "And, we'll visit each other on occasion. But, all my other friends are here. And also... that brings me to my second bit of good news."

The girls listened intently.

"I told Flash Sentry that I fart more than the average human, and that it smells twice as bad. And, he wasn't disgusted at all. He actually has a fart fetish. He said I could tell you about it. So, we're perfect for each other."

"That's... great news," said Rarity. She didn't want to imagine the fun they'd have together, but she did feel happy for Sunset all the same.

...

After lunch, Rainbow Dash and Rarity walked toward Rainbow Dash's house so she could change for a game of beach volleyball. The two of them signed up to be on the same team.

"So Rares, thinking about giving up yet?" said Rainbow, sniffing Rarity and getting a whiff of her pungent odor.

"I don't like it, but I think I'm getting used to my smell," said Rarity. "And to... breaking wind in a rather unladylike manner. What about you?"

"It is a little annoying, but I can do it for a month if I wanted to."

Suddenly, Trixie bumped into Rainbow Dash. Rainbow froze in her tracks. Trixie turned around and sniffed Rainbow.

"Well, Rainbow Dash, it looks like you finally decided to wash," said Trixie. "Too bad you threw away your only weapon."

"It wasn't my ONLY weapon!" said Rainbow, getting into a karate pose.

"The Great and Powerful Trixie will have her revenge!"

Before either one of them could attack, Rarity casually forced Trixie's face into her stinky armpit. Trixie squirmed frantically, finally getting free of Rarity and falling on her back.

"Tell me this isn't happening," said Trixie. "Now RARITY smells bad? What is this world coming to?"

"Hopefully better attitude from you," said Rarity. "This is for tossing me into the mud." She squatted down so that her behind was positioned directly in front of Trixie's face, with very little distance between them. Rarity's butt smelled bad on its own from not showering for a week, but it stunk even worse in Rainbow's shorts.

And, as if that wasn't enough, Rarity farted as loud and hard as she could. Three long, explosive farts blasted out of her rear directly into Trixie's face. The third fart caused her to pass out.

"Did I overdo it?" said Rarity.

"She's alive," said Rainbow, noticing Trixie's chest moving. She held out her water bottle and splashed a bit of water on Trixie, waking her up.

"Ugh," said Trixie, sniffing Rarity's farts and feeling like she was going to be sick.

"Don't pick on me or any of my friends again, and don't breathe a WORD of this to anyone else, or I'll do it again, and mark my words, I'll smell twice as bad then."

Trixie got up and ran as fast as she could.

"Wow, Rarity," said Rainbow Dash.

Rarity blushed a little. "I had to show her," she said. "Please pardon that unladylike display."

"Are you kidding? That was awesome!"

Rarity giggled.

...

Six days later, it was the last day of their bet, and neither Rainbow Dash nor Rarity had lost. Rainbow was still perfectly clean, and Rarity smelled really bad now, and was constantly farting, putting a little more fart powder on her meals than before.

"I honestly can't believe you lasted this long," said Rainbow. She sniffed Rarity and recoiled. "Ugh, you smell horrible!"

Rarity giggled. "I know I do." She lifted her leg and unabashedly let out a boisterous fart, sighing of relief. "I can't believe you lasted this long either."

"Are you kidding? It's really not that hard. Sometimes I have a hard time smelling my skirt. I can't believe I smelled that bad."

...

The next day, Rarity got out of bed. The bet was over now. It had ended in a tie. She walked over to the shower to turn it on... and then stopped. She didn't know Rainbow Dash hadn't lost the bet at the last second. She had to make sure first.

Or at least that was the excuse she gave herself.

They met at Twilight's house.

"Congratulations," said Twilight when she opened the door. "You tied! You both lasted the full two weeks. You even went the extra mile. Rarity didn't shower this morning, and Rainbow Dash did."

"What?" Rainbow and Rarity looked at each other.

"Now you can go back to the way you were," said Twilight.

"Nah, I'll stay clean a little while longer," said Rainbow Dash. "Maybe we'll extend it to three weeks. What do you say, Rarity?"

Rarity farted loudly in response.

"I take that as accepting my challenge."

"But Cherry Fizzy will be disappointed if you don't smell like... Rarity does now," said Twilight, fanning the air a bit. "And Rarity, a week ago you couldn't wait to shower."

"All the more reason you won't be able to go on much longer," said Rarity.

"He still likes me," said Rainbow.

...

The girls all ate lunch together at Pinkie's house. The other girls seemed to be whispering something to each other. Rainbow Dash and Rarity weren't sure what they were talking about. Probably how they didn't expect them to stay in their new positions for so long.

Rarity let out a loud fart for about five seconds. Pinkie Pie stifled her laughter, thankful she had used the bathroom before lunch.

"Rarity!" said Rainbow Dash, fanning the smell away with her hand. She didn't notice Pinkie sprinkle something on her sandwich.

...

After lunch, Pinkie and Applejack walked with Rainbow to Sweet Apple Acres. As they walked, Rainbow felt extremely gassy. She wasn't sure why. She hadn't eaten anything on Rarity's list. But, she didn't want to fart and lose the bet.

Once they reached Sweet Apple Acres, Applejack said "Congratulations on stayin' clean for two whole weeks. Have some cider as a reward."

Rainbow eagerly drank all the mugs of cider, Applejack gave her, while doing her best to hold in her farts.

The cider went through her rather quickly and soon she needed to pee. "I'll be right back, I gotta go to the bathroom."

"Now," said Applejack. She and Pinkie picked Rainbow Dash up by the arms and threw her facedown into the pigsty.

As soon as Rainbow splashed into the mud, she released a series of wet farts. And something else which made the mud wetter. She wasn't the only one, for Pinkie Pie was laughing her butt off at Rainbow's flatulence, especially when it blew her skirt back a bit. Once Rainbow was done (after over a minute), she sat up and looked at how dirty her dress was.

"Ugh!" said Rainbow Dash. "Wait... no, I don't have to pretend anymore. I forgot how fun it is to fart and be dirty like this." She farted again and laughed.

"We thought this would remind you," said Pinkie Pie. "That's why I put fart powder on your sandwich!"

"The bet's still over, right? Anything today doesn't count, right?"

"Yes," said Applejack. "You tied."

"What do you say we wash Rarity now?"

...

Rarity sat in her living room, farting non-stop, when someone knocked at the door. She opened it. Rainbow Dash, Applejack, and Pinkie Pie stood on the other side.

"Ha!" said Rarity upon seeing that Rainbow was covered in mud. "I win!" She shook her butt at Rainbow, farting loudly as she did so.

"No, we tied," said Rainbow. "The bet's over. It ended today. And even if it didn't, I didn't break the deal. They did."

"I'll prove I can go twice as long as you!" Rarity farted again.

"I don't think so. Rarity, you're getting a bath!"

"I beg your pardon? Ooh! Unhand me!"

Applejack and Pinkie Pie grabbed Rarity's arms and dragged her to the bathroom, kicking and pouting.

"Phew, you smell just like Rainbow Dash used to," said Applejack.

"Wait!" said Rainbow Dash. "I want my outfit to stay like it is." She stripped out of Rarity's muddy dress into her pink underwear, stepped into the shower, and rinsed herself off. Then, while Applejack and Pinkie Pie held Rarity down, Rainbow pulled off Rarity's smelly outfit, leaving her in her dirty grey underwear.

Rainbow put her outfit back on, sighing in satisfaction at the smell, and put Rarity's dress back on her. Rarity didn't resist this much, as she saw how dirty her dress was.

"It... kind of smells a bit," said Rarity. "Did you... Aah!"

Rainbow Dash threw Rarity into the tub, soaking her dress instantly.

"Maybe you two better leave for this," said Rainbow Dash. "She'll be more comfortable that way. Thanks for the help."

"No problem," said Pinkie. She and Applejack gave each other a high five and walked out the door. They were sure their mission had succeeded.

Rarity splashed about in the tub, and Rainbow chuckled, remembering the irony of when they had been in opposite positions. She poured Rarity's favorite bath soap on a sponge and started scrubbing Rarity's armpits.

Then, Rarity farted in the tub. She giggled a bit, but blushed, as if she was starting to remember how unladylike she thought it was.

"Rarity!" said Rainbow Dash. "Girly girls don't fart! Your butt needs a good scrubbing!"

Rainbow got Rarity on all fours and scrubbed her butt as hard as she could, lathering it with suds.

"Rainbow Dash! What are you doing? Ever hear of personal space?" Rarity was now blushing beet red.

Rainbow lifted Rarity's skirt to scrub her panties. She knew she was cleaning her own dirty pair of underwear, but she decided she'd wear the pink underwear from now on, let it get as dirty as the rest of her, and let Rarity do what she would with her old pair. She finished scrubbing, and started to scrub her armpits again, and then her back, repeating the bath Rarity had given her. Rainbow remained dry because Rarity wasn't splashing anymore, as if she was enjoying the bath, being scrubbed of all her sweat, grime, and odor.

"Please don't pee in the tub and make me wash you again," said Rainbow Dash once she'd rinsed Rarity with the shower head.

"Oh, heavens no," said Rarity. She sniffed her armpit and let out a satisfied sigh, as she smelled only traces of soap. "I forgot how much I hate being dirty."

"All you needed was a nice bath."

"Thank you so much, Rainbow Dash. You're a true friend. We still tied, right?"

"That's what I was trying to tell you, but you were too busy farting."

Rarity blushed. "I don't know what got into me. I will never be so unladylike again. And I'm dreadfully sorry I underestimated you, Dashie. You really could be clean forever if you wanted to."

"I did kind of like it. I just forgot I like being grungy better. And, I also underestimated you, Rares. You seemed to be really enjoying yourself for those last few days."

Rarity blushed. "I suppose even the most ladylike of girls can get carried away. But not a word about this bath to anyone, understand?"

"All our friends were in on it. But, I'll keep it quiet to everyone else. Except Cherry, of course. I know he'd like to hear about it. I told him about how you gave me a bath, after all. And I'll tell him every juicy detail of how Pinkie and Applejack got me to be dirty again." Including what she had done in Rarity's dress, which she decided not to tell Rarity about.

"Fine, but no one else."

Rainbow farted loudly and laughed.

"Rainbow Dash!" said Rarity, wrinkling her nose in disgust. Then, she laughed along with Rainbow. Things were back to normal.