"Yukkooooooo…" The long, drawn-out whine of her name, followed by the whumph of a body flopping down onto a mattress, registered to Yuyuko, but did not break her focus on her schoolwork. "How come you're always up so late studying like this? No wonder you spend the whole day sleeping."
"I just have a different circadian rhythm," She said, not even bothering to turn and look as Rui splayed herself out on her bed. "It's an evolutionary advantage. Night owls are needed to keep the rest of the tribe safe while they sleep, you know."
Rui groaned. "Safe from what? We're in a school dormitory."
"Well, you never know who could sneak up on Tamao-senpai in the night." The corners of her mouth turned slightly upward at Rui's girlish scream.
"D-don't bring her into this!" This time Yuyuko couldn't resist turning around to get a look at Rui's furiously blushing face, although she only managed to get a short glimpse before it was buried into a pillow. Ah well, the effect was the same. And it was adorable. She loved Rui for many reasons, and the ease with which she could be flustered was one of them. "Tamao-senpai probably doesn't…" Rui opted not to finish her sentence and instead screamed into her pillow.
"You're right, Tamao-senpai can probably defend herself pretty well," Yuyuko said, rising from her chair and moving to take a seat on the bed. She had a better view of Rui from here. The best view, in fact, when Rui raised her head from the pillow ever so slightly to look up at her, even more of her embarrassment now visible.
"Yukko, please…"
"Please what?"
"Aaaargh! You know what you're doing!"
Yuyuko smirked slightly. "Oh Rui, you're so much fun to tease." Rui just groaned before rolling over onto her back, a cute little pout on her blushing face. "You are just too cute." Rui turned her head to look away, and now that her neck was visible Yuyuko could see that even it had turned scarlet.
Yuyuko put a thoughtful finger to her lips. She was getting away with an awful lot tonight. How far would she be able to go? Slowly, carefully, she moved, repositioning herself so she was straddling Rui's waist.
"Hey."
Rui was practically glowing red as she slowly turned her head to look up at Yuyuko. Her brow was slick and shiny with sweat, and steam could almost be seen coming off of it. "Y-Yuyuko, what are you doing?"
"Appreciating the view." As she looked over Rui's flustered form something caught her eye. The bottom of her shirt had ridden up slightly, revealing the tiniest hint of her toned stomach. Yuyuko's smirk grew slightly. She'd already gone this far. She might as well indulge a little.
"And maybe a little more," She said as she reached out to lightly run a finger over the exposed skin. Rui immediately went rigid at the touch.
"Ahaha, h-hey, Yukko, y-you know how I feel about being t-touched like that," Rui said nervously as Yuyuko's fingertips lightly ghosted over her stomach. "I...hahaha...it's...ha…"
"It's what?" Yuyuko said, before sliding her hand under Rui's shirt and gently tickling the spot below her navel.
"HYEEEAAAAGH!" Rui's scream, and the hysterical laughter that followed, almost seemed disproportionate to Yuyuko's rather light touches. How the hell did Rui even get so ticklish? It was something Yuyuko had discovered when they were younger, and upon its discovery Rui had become vigilant in making sure Yuyuko's hands remained a healthy distance from her bare skin. Of course Yuyuko respected her personal space when they were in public, it was common courtesy, but at times like this, when it was just the two of them and Rui's guard was down, there was room for a little bit of teasing.
"How do you even wear shirts if this is how you react when I touch you?" Yuyuko said, sliding her other hand under Rui's shirt and dancing her fingers outward toward her sides. Rui let out a high-pitched squeal in response.
"It's not-HYAhaha!-it's not the fabric!" She said as soon as she was capable of speaking. "It's because it's youAHAHAHYA!" Rui began squirming helplessly as Yuyuko's hands reached her armpits, the feel of quick and dexterous fingers on skin that was rarely touched momentarily overloading her brain. Her shrieking laughter was incredible enough that Yuyuko almost felt like she could get lost in it. Almost. Something else had come to her attention.
Something was pressing up between her legs. Something hard. While only slowing down the tickles just slightly, Yuyuko lifted herself up to get a look at what it was. Her eyebrows went up slightly as she noticed the slight bulge in Rui's shorts.
So she gets off on this, Yuyuko thought, feeling a slight twinge of her own arousal below her stomach. No wonder she doesn't like when I do this around other people.
"H-hey...Yukko...hahaha…" Rui breathed. In the surprise of her discovery it seemed that Yuyuko had paused the tickling. "Are you...are you done?"
Yuyuko took a moment to think. While she certainly wanted to keep going (things were just getting good, after all), if this was how it was for Rui then the last thing she'd want to do was push her. "Do you want me to be done?"
Rui turned her head to the side, the blush around her cheeks darkening. "Well, I...I wouldn't...mind…" She swallowed hard before lifting a hand and pointing to the dresser. "There's some p-protection...i-in my drawer…"
Yuyuko's smile took on a more genuine glow as she reached out to gently stroke Rui's hair. "Oh Rui, you're so thoughtful." The mischievous edge returned to her face. "You weren't planning this out, were you?" Yuyuko giggled as she watched Rui's face re-explode into a blush.
"N-no! I'm just really prepared-HYAAAAAAA!" Yuyuko had quickly lifted Rui's shirt, and now her hands were roaming over every inch. Her stomach, her sides, her hips, under her arms, nothing was safe from her now much more aggressive tickles. Rui shrieked and screeched and laughed like she had lost her mind, wriggling beneath Yuyuko as she continued to torment her.
"Yukko, you-AHAHAHAHA!-you have to staHAHAHA!"
"What's that?" Yuyuko teased, leaning in as she intensified the tickling even more. "I can't understand you."
"HYAHAHAHA!" Rui laughed helplessly, tears now streaming from her eyes. "Yukko I'm-AHAHA-I'm going to-HAHAHA...aaaahhh…" Her whole body went stiff as she let out a long, drawn out moan, followed by several similar ones. Yuyuko's eyes widened, and she lifted her hips to look down again.
"Oh my god." There was now a large, dark stain on the front of Rui's shorts. "Did you just…"
"Yukko…" Rui sniffled. "I'm sorry Yukko…"
"I can't believe this, Rui." Yuyuko said with a slight laugh. "You just came from being tickled." Rui groaned and covered her face in embarrassment. "Actually on second thought I can totally believe it."
"I'm sorry!" Rui said again, her voice muffled by her hands." Yuyuko smiled before leaning in to kiss her temple.
"Sorry for what? Being adorable?" She relished Rui's embarrassed squeal before rolling off of her to admire the full extent of her handiwork. "But you will have to change out of those shorts though, I can't have you sleeping in your own mess."
Rui, naturally, screamed.