Rarity came over to Rainbow Dash's house one day. She was wearing a skintight pink romper.

"Looking good, Rarity," said Rainbow Dash.

"Why thank you, Dashie," said Rarity. "I made you something too." She held up a pink sleeveless dress. It wasn't very puffy but looked very beautiful and went down to the knees.

"I don't usually wear those," said Rainbow Dash.

"But I really like the contrast of one as tomboyish as you wearing a pretty dress like this."

"Well..."

"And I love the double contrast of a girl in a pretty dress farting and doing other unladylike things." She winked.

"Heheh, you have a point there. All right, I'll try it on." Rainbow removed her shirt and her pants, so that Rarity could see her stained yellow boyshort panties from their camping trip. They still had brown stains at the butt. Rainbow put on the dress.

"You look smashing," said Rarity.

Rainbow blushed and chuckled. She poured several glasses of soda with fart powder and drank them. Rarity drank some as well, but Rainbow drank twice as much as her. Soon Rainbow Dash was farting up a storm, chuckling at how this must look with her in a dress. And Rarity let out some explosive wet farts as well, stinking up her romper. At one point, she positioned herself with her head down and her rear end in the air facing Rainbow Dash.

PPPPPPPFFFFFFFFFFFRRRRRRRRRT!

"Nice one, Rarity," said Rainbow Dash, slapping Rarity's butt. Rarity giggled and let out a short, boisterous wet fart.

Eventually, Rarity said "How would you like me to restyle your hair?"

"Well... If you really want to."

"Wonderful! I brought everything I need for that."

They walked into a room they thought would work for this. Rainbow sat in a chair and Rarity started working on her hair.

They were clear of the fart smell but Rainbow could still pick up an unpleasant odor. "Rarity, you kinda smell."

"Oh. Yes, I haven't washed for three days. But of course we'll have our usual bath today or tomorrow morning. And also..." FFFFFFFRRRRRRT!

Rainbow Dash chuckled.

Rarity finished styling Rainbow's hair to look like her own, including the color, and showed it to Rainbow in the mirror. Then she started styling it another way.

Soon Rainbow Dash had to go to the bathroom. "Rarity, can we take a break? I have to pee really badly."

"You're staying in your seat until I've tried every hairstyle I can think of."

Rainbow fidgeted in her seat as Rarity styled her hair to look like Sunset. Then Twilight, then Fluttershy.

"How much longer is this gonna be?" Rainbow was squirming. "I REALLY gotta go!" She accidentally farted.

"It will go for quite some time," said Rarity. "And try to sit still so I can have an easier time with your hair."

Rainbow sat as still as she could. This was enjoyable for her, adding an extra challenge to her ability to hold it, much like being tied up kept her from holding herself or crossing her legs.

Pinkie's hairstyle came next, then Applejack. After that, Rarity un-dyed Rainbow's hair, returning it to its rainbow color. By the time this was done, Rainbow felt like she was about to burst. Rarity tried several different hairstyles for Rainbow Dash, and she was just on the third, when Rainbow couldn't hold it anymore. She peed in her dress full force, sighing of relief as her crotch and butt became soaked, and yellow waterfalls poured off her chair and onto the floor.

"I see you couldn't hold it anymore," said Rarity with a smile.

Rainbow chuckled, not bothering to feign embarrassment this time. Rarity was right, it was fun peeing in a dress.

After Rainbow finished wetting herself, Rarity styled Rainbow's hair to look similar to her pony counterpart at the Gala. By now she also needed to pee. So she sat on Rainbow's knee and peed herself, soaking the crotch and butt of her romper and further wetting Rainbow's dress as she sighed in relief.

Rainbow took pleasure in the feeling of Rarity wetting herself while sitting on her. The warm wetness of Rarity's pee was just as fun as soaking herself with her own pee.

Once Rarity finished peeing, she let out a loud, long, deep-pitched fart. BBBBBBBBBBRRRRRRRRRRRRRT!

Rainbow loved the feeling of Rarity's butt vibrating against her, especially in her wet, stinky romper. When Rarity finished farting, Rainbow put her over her knee and spanked her. Rarity squealed with each swat and droplets of pee flew from her tush. Rainbow never got tired of slapping Rarity's butt in skintight pee-soaked outfits, nor did Rarity get tired of being spanked in such a state. The ninth swat made her fart.

Once Rainbow was done, she said "I peed in my dress. That was so unladylike. I need a spanking too."

They swapped positions. Rarity spanked Rainbow ten times. Then she lifted her skirt, exposing her wet, stained underwear. Rarity enjoyed the sight of Rainbow's tushie in these dirty skintight boyshort panties, and Rainbow enjoyed being in this position. Rarity slapped Rainbow's butt ten more times, both girls taking immense pleasure in this. Rainbow farted a few times during the spanking.

Afterwards, they had some more fun together. They had a big meal of beans, which made them fart even more. At one point they pressed their butts against each other and farted repeatedly. Both girls let out explosive wet farts, many of which were very long.

They were sitting on the couch watching football when their farts got wetter and stinkier. Soon Rainbow Dash farted too hard and soiled herself. She chuckled, wiggling her butt around and feeling her mess squish under her.

Rarity felt an urge to poop as well. She got on all fours with her butt facing Rainbow Dash, and released a lot of hyperscat into her romper, sighing of relief as a brown bulge appeared on her butt. Rainbow Dash sniffed the mess she had made. It smelled horrible, and she loved it. Rarity sat back down, wiggling her butt around in her mess as well. She let out a sloppy wet fart, soiling herself further.

Eventually, they washed each other in their soiled outfits and changed into their pajamas. What followed could be easily predicted.

Author's Notes:

A little bit shorter but I wanted to do something a little different, putting Rainbow Dash in a dress, and it took a while to decide what outfit to put Rarity in and I realized I haven't done as much romper fetish fuel as I wanted to.