‘Cross reference the cells, close the brackets, hit the button and... done!’

With a triumphant grin, Carrie Juniper leaned back in her chair and looked over the spreadsheet on her laptop. Everything appeared to be in order and all of the lookup formulas were working as she intended. Granted, the project wasn’t due for at least another week but, unlike her sisters, Carrie was never one to leave things to the last minute, and she would always tackle anything as soon as she could. While she looked over the formulas, Carrie noticed just how late it had gotten. Without even knowing it she’d spent nearly two hours working on the project and it was now nearing five in the evening.

“Better clear this all up and head home. I’m probably delaying the library from closing,” Carrie mused to herself as she saved the spreadsheet three times before finally closing out of it and putting her laptop in sleep mode.

Clearing down the table was relatively quick as Carrie refused to work in a messy workspace, so the majority of things were already organised enough to be put away easily. Carefully slipping off her reading glasses and returning them to their case, Carrie’s eyes fell upon the empty water bottle that she’d left on the table. A small pang from her abdomen alerted her to the fact that she’d probably drank the whole thing over the course of her work and was now feeling the after effects. Well, one more pit stop before leaving school wouldn't hurt.

Once Carrie was all tidied up and ready to go, she made her way out of the school library and towards the closest set of toilets. Giving the handle a testing push, Carrie found that she might’ve been a bit too late to stop by, the door being firmly locked. Tutting in frustration, she opted to ignore the other toilets around the school building, certain that they were locked as well. With no other options, Carrie made her way towards the main entrance to begin her walk home.

As Carrie passed by the windows of the connecting walkways between the school blocks, she quietly grumbled to herself as it looked like the rain from earlier hadn’t let up in the slightest; in fact, it had gotten worse. Thick sheets of rainfall rhythmically drummed against the walls of the walkway, reminding Carrie of her own internal walls with a shudder. Thankfully, as long as there were no delays, she was certain she’d be fine. The pangs from her bladder, while incredibly vexing, weren’t that bad at the moment. Arriving at the main entrance hall, Carrie looked through her bag for her umbrella which she held at the ready to open up as soon as she stepped outside.

“Sis! You gotta help me!” A pleading whine came from behind Carrie. Turning to the source of the voice, she shook her head in disbelief at the sight before her. There stood Cleo in a sodden semi-translucent shirt and a healthy red blush on her face. Her bag was held in front of her chest, almost as if she was trying to hide something more than just a visible bra.

“Did you forget your umbrella again?” Carrie replied tersely. “Honestly…”

“Worse.” Cleo whimpered as she moved her bag from its defensive position.

Carrie could hardly believe her eyes. Not only had her ditz of a sister forgot her umbrella, she’d also forgot something far more important. Despite her warning her beforehand each time, Cleo still forgot to pack a bra in her sports bag before leaving the house that morning.

“You’re such a moron…” Carrie sighed as she rubbed the bridge of her nose to stave off an impending headache.

“Please?” Cleo looked at Carrie pleadingly.

“...Fine. Just make sure this is the last time, okay?”

Try as she might, Carrie couldn’t leave her sister in the sopping state she was in at the moment, regardless of whether it was her own fault or not. Cleo joined her under the umbrella with a delighted giggle and the two of them set off for home. It was rather awkward having two people under a single umbrella, especially when one of them pretty much had her bag glued to her chest, but at the very least it provided some company for the walk and an excuse to keep Carrie’s attention off the pitter-patter of the rain. Due to the weather, and the fact that it was peak rush hour traffic, the usual twenty minute walk home may take longer, which was not something Carrie was looking forward to. If she were alone, she might’ve resorted to some covert means of aiding in her ability to hold back the tides, but that wasn’t the case, and her own pride prevented her from dropping her usual sensible big sister act. This was just something she had to tough out and, though it was pretty bad, Cleo was likely having a far worse time. From the corner of her vision, Carrie was certain she could see Cleo occasionally shivering when the cold winds blew, gently bouncing on her heels at pedestrian crossings. For reasons other than her original concern, it was best if they hurried on home as fast as they could.

When they reached the park bordering their neighbourhood, Carrie’s bladder was just about reaching its limit. From both the cold winds and the rain, the once niggling pressure had become a persistent ache that refused to go away. Her walking had become more stiff as she didn’t want to run the risk of overexerting her muscles more than necessary. In a similar fashion, it seemed Carrie wasn’t alone in her struggle as Cleo’s pace had become slower as well, and she could hear faint whimpers from her whenever there was a gust of wind. ‘As if we both need to go at the same time., Carrie thought to herself.

“Can we stop? Please?” Cleo asked, worry evident in her tone.

“No, we’re nearly home. I don’t fancy getting soaked standing around,” Carrie protested, prompting a small yelp from Cleo at the word ‘soaked’.

Suddenly, Cleo grabbed her by the hand and dragged her off towards the trees, giving no explanation other than a hurried request to keep a look out and a thrusting of her bag into Carrie’s hands. The sudden movement caused a sizeable leak to escape Carrie’s hold, leading to a surprisingly comfortable warmth in her panties.

Before she could even follow through with Cleo’s instructions, her sister had already yanked down her noticeably wet panties, coupled with a faint yellow stream cascading between her thighs, and squatted at the base of a tree with good cover. Accompanying the sound of the rainfall was a much closer and more sporadic splattering of liquid against the leaves covering the floor. This wasn’t a sound that Carrie wanted to hear, and she lacked the free hands to block it out, so with a strong crossing of her legs and a slightly bent posture, Carrie endured the pressure in her abdomen while her sister got some much needed relief.

The short wait until Cleo was finished was pure agony for Carrie, and it showed in every little leak that escaped her. Carrie could barely keep the flood at bay and the leaves beneath her were getting wet with more than just the rain. The second that Cleo nudged Carrie the roles were reversed. Carrie handed off everything in her hands over to Cleo and dashed towards the same tree that Cleo had marked. Fumbling with her panties, Carrie didn’t even bother pulling them down any lower than her thighs, and simply held them away from the source of a powerful stream that put even the atmospheric downpour to shame. Though she had tried to salvage her panties, there was no doubt that they were drenched through to the point of no return. Still, she’d avoided the worst, so that was something. As her personal rivers tapered off into dribbles, Carrie made a mental note to herself to never allow something like this to happen again. Shaking herself dry, Carrie pulled her wet panties back up, cringing at the feeling of the damp fabric against her most sensitive place as she rejoined Cleo.

“Not a word of this to anyone, and I won’t tell them that you went a whole school day without a bra,” Carrie cautioned Cleo.

“You don’t need to tell me twice,” Cleo answered with a blush.

With each of their secrets safely secured, the pair returned to their journey back home.