About a week later, the girls were relaxing on the beach, wearing their swimsuits. It was pretty hot once again, so they each drank a lot of slushies.

Until Rainbow Dash said "How about we go for a swim?"

The girls all made sounds of agreement. Sunset and Rarity removed their skirts, revealing a black bikini and skintight purple swim shorts, respectively.

Sunset had to go to the bathroom really badly from all the slushies she had drank. Twilight, Rainbow, Pinkie, Rarity, and Applejack had all used the beach bathrooms at least once where Sunset had held it. Now that she was about to go into the water, Sunset had the perfect excuse to do something a little naughty.

Sssssssss...

"Ahhhhh..."

The other girls stared at Sunset as she peed her swimsuit. Twilight blushed lightly but giggled, knowing Sunset was enjoying herself more than the others would know. Pinkie and Rainbow also giggled quietly.

Sunset's heart was beating a little fast at peeing herself in front of all her friends instead of just Twilight. It wasn't like none of them had seen her in wet pajamas or shorts before, but them seeing her deliberately wetting and enjoying it felt... exciting.

As the pee flowed down her legs and soaked the sand where she stood, Applejack said "Hoo, nelly! You really needed to go!"

After about two minutes, she finished peeing and sighed of relief.

"Are you all right, darling?" Rarity asked.

"I'm fine," said Sunset. "Swimsuits are meant to get wet, so what's a little pee?"

"You really looked like you were enjoying yourself there," said Pinkie.

Sunset blushed.

"Not that I blame you," continued Pinkie. "Peeing your swimsuit's really fun!" Pinkie started peeing and sighed of relief as her swimsuit became soaked and pee flowed down her legs. "Ahhhhh..."

Everyone laughed, then they went for a swim.

Fluttershy swam up to Sunset. "You really like peeing your swimsuit, don't you?"

Sunset blushed a little. "Yes. It feels so warm and wet and... I don't know how to describe it."

"You don't have to." Fluttershy also blushed. "You don't know how many times I peed in my wetsuit when no one was looking. It just feels so nice, plus then I don't have to make a fuss about using the bathroom. I know I'm wetting my shorts underneath but I'm going to get them wet anyway under the wetsuit, so..."

"So you like how it feels too?"

"Yes. It's still a little embarrassing when I get really scared and pee in my dress or shorts, but when no one else can tell... I'm such a dirty girl."

"Don't feel bad. I love it too, and so do Pinkie and Twilight. And even if you messed yourself, we'd still love you."

Fluttershy smiled. Sunset could feel the water around her getting warmer. Fluttershy blushed lightly but giggled.

Author's Note

I made up what Rarity's wearing under her skirt, Sunset's was already confirmed.