Fluttershy lay on the beach with her friends. She always wore her wetsuit to the beach even if she wasn't swimming. And in case she ever needed to take it off, she wore a sports ouftit underneath instead of a bikini. It consisted of short, skintight green spandex shorts and a matching sports bra.

As a result of wearing a wetsuit in the sun, Fluttershy got very hot, and sweated a lot, so that there was actually a thin layer of sweat trapped in her wetsuit, which she would sometimes have to drain by pulling open the leg hole of her wetsuit occasionally.

Of course, this also meant she needed to drink a lot of water to stay hydrated.

So, after about an hour, she really needed to pee. She held it for the moment, and fidgeted slightly, but only slightly, trying to hide how badly she needed to go. Twilight noticed this, but didn't say anything.

Fluttershy was a little shy to ask to use the bathroom, and plus she was feeling like cooling down in the water, so she spoke up.

"Would anyone like to go for a swim?"

"Sure," said Rainbow Dash. "Applejack, how about a swimming race?"

"You're on," said Applejack.

The girls all walked into the water. Once swimming, Fluttershy felt the water enter her wetsuit through the openings in the top, soaking her completely. This increased her need to pee, but now that she was in the water it didn't matter. Fluttershy put on her diving mask and dove underwater. As she did, she made sure she was a fair distance from the other girls, and started to pee in her wetsuit. She closed her eyes and enjoyed the relief as the warmth spread through her wetsuit, becoming a part of the layer of water trapped between her and it.

Once she was done peeing, she continued to swim around, enjoying both the relieved feeling of no longer needing to pee, and the underwater scenery and sea creatures.

Eventually, Fluttershy returned to shore. Twilight was already there. Fluttershy drained her wetsuit again. She pulled on its collar a bit and sniffed the inside. She could smell pee inside her wetsuit, but she was sure no one would be able to smell it from the outside.

She walked over to Twilight, blushing a little and trying not to look embarrassed. "Um... that was a fun swim, wasn't it?"

"Yes, it was," said Twilight. "And, by the way, if, for any reason, you felt like peeing in your wetsuit, you wouldn't have to feel ashamed of it. Virtually everyone who swims or surfs in a wetsuit has urinated in it at least once. So it's not really weird or unusual."

"Really?" said Fluttershy.

"Of course. I've done it before when scuba diving last month, and I did research on it before that."

"Well, that's good, cause I just did that in the water."

"I thought you did. I wanted to reassure you, while pretending I didn't notice."

Fluttershy felt the rest of her drinks on the beach go through her. So, she peed her wetsuit again, sighing of relief. A bit of her pee dripped out of the leg holes. It felt weird to pee herself in front of Twilight, but if Twilight was right she didn't have to feel that it was.

Twilight heard the hissing sound, and realized what was going on. "They usually do that in the water," she said.

"Oh." Fluttershy blushed, but giggled, and drained her wetsuit again.