"Wh…?"
Lynn had just entered her room. She expected to see her sister Lucy lying on her bed, reading or writing something. Hell, she wouldn't have been surprised if she was masturbating.
She didn't expect her to be trying to climb into the vents.
Ten years ago, and even sooner than that, Lucy was small enough to move through the ventilation system. It was how she had the knack for showing up practically anywhere. Then, when she was twelve, puberty hit her like a freight train. She shot up in height, her hips widened to the point of rivalling their mother, and her rack filled out basically overnight. At eighteen, she was now both the most curvy and tallest of all of her siblings.
Lynn, meanwhile, was nearly the opposite. She was the shortest, with the exception of Lisa and Lily, and that was simply because they hadn't grown up yet. Her figure wasn't as full, too. It normally didn't bother her, unless she saw some cute boys flirting with Lucy (often unsuccessfully) or she accidentally ran head-first into her boobs when she rounded a corner too hard.
Lynn snapped out of her introspective thoughts. "What are you doing…?"
Lucy's legs flailed a little. "I was trying to climb into the vents but got stuck."
Lynn crossed her arms. "Why'd you think that was a good idea?"
"I… I just wanted to see if I could. I missed being in there."
Lynn sighed. "Well, lemme see if I can get you outta there." She approached her sister, kicking the chair below her and wrapping her arms around her. "Ready?"
"I think so."
"One, two, three…!" Lynn began pulling down hard. Lucy barely moved. Lynn tried to put all of her weight into it, lifting her legs off the ground. Still, Lucy didn't move.
Clearly this wasn't comfortable for Lucy, if her subdued pained grunts were anything to go by.
Lynn could feel her grip slipping. Before she could do anything about it she hit the floor, landing on her backside with a grunt. She opened her eyes, and saw pale. She looked back to her arms, a pair of black jeans in them. Then back up, Lucy's exposed backside barely concealed by a pair of black underwear.
"Ah, Lynn…!" Lucy hissed. "What the hell?"
"Dang it, sorry Luce!" Lynn immediately bolted upright. She found herself standing pretty much level with her butt, and she couldn't help but stare.
Lucy sighed, going limp. "Just kill me now. Better that then dying of embarrassment."
Lynn had an idea. A sick, twisted one, but it's not like she hadn't crossed that line before. She smirked. "I dunno, Lucy, there's not much to be embarrassed about." She gave one of her cheeks a light smack, which made Lucy recoil.
"Lynn…!" She hissed, both in embarrassment and in anger.
"Besides, I know this is a fetish of yours." She gently rubbed the same cheek. "I've read your stuff, I know you like the idea of being stuck and having someone bang you."
Lucy squirmed under her touch. She was already getting a touch damp, her thighs rubbing together. "W-wait…"
Lynn took a few steps to her other side, licking her lips. She hooked her fingers around Lucy's underwear and pulled it down, slowly, tantalisingly.
Lucy wanted to kick Lynn away, but she felt herself unable to. Not because she had frozen in fear or any primal instinct like that, but because Lynn was right. Being stuck in a cold, dark place, unable to stop someone or something from ravaging her (currently) virgin holes… that was her biggest turn-on. She just never expected her sister to be the one doing the ravaging.
She felt Lynn's hot breath on her nethers, and she bit her lip to stifle a moan. Lynn chuckled, massaging her thighs. "Looks like someone's eager."
Lynn used her thumb to pull her outer lips aside, the sound of sticky flesh peeling apart ringing out in the otherwise silent room. She mirrored herself with her other thumb, spreading her slid wide open. It was already slick with arousal. She leant in and gave her a small kiss on her clit, sending a jolt up Lucy's spine.
"Lynn…" Lucy moaned out, softly. If she got too loud, the whole house would probably hear her.
Lynn smirked, stroking Lucy's snatch with broad, gentle strokes, her hand effortlessly gliding along. After a moment she slowed down, and gently slipped her finger into her entrance.
Lucy squirmed under her touch, covering her mouth to stop her noises of excitement from escaping. Lynn moved again, standing to her side and slipping a couple more fingers in, her other hand rubbing her clit. She skipped the gradual buildup of speed and went full-force. "Let's see what you cum like~"
Lucy covered her mouth and held her voice back as much as she could, as her climax rapidly hit her. Her whole body bucked and shook as she rode it out, Lynn pulling out entirely so she could watch.
"Woah, that's a good distance." Lynn said, admiring the spurt of fluid that had shot out of Lucy's nethers.
Lucy finally came down from her high. Her legs dangled from her position, weak and limp from the waves of pleasure. She then noticed she was dangling just a little bit lower, her breasts now closer to her face and the rim of the ventilation shaft now a little more tucked under her arms. "L-Lynn?"
"Hm?"
"Do that again."
Lynn smirked. "Someone's eager."
"I-It's only to get me out if thi-" Lucy interrupted herself with a long, drawn-out moan, as something wet and hot dragged itself along her still-sensitive slit. "Nff… Easy there…"
Lynn smiled, then licked a few more times. One of her hands reached up and grabbed a handful of ass, the other wandering down her own body and sliding underneath her shorts, giving herself some much-needed attention. She moaned, the vibration adding to her ministrations on Lucy.
She switched between broad strokes with her tongue, to flicking her clit with the tip, to cupping her lips around it and gently sucking on it. Meanwhile, her hand worked double-time, stopping for only a second just to discard her shorts and give herself more room to work with. Her climax was just on the horizon, and the moment she hit it she threw her hand away from herself and grabbed Lucy's other cheek, burying her face in her crotch and screaming.
The sudden contact of another hand on her behind, and more notably Lynn's muffled screams rocking through her body, was enough to tip Lucy over the edge. She let out a loud half-scream half-moan, giving up on trying to hide her noises.
Even through her orgasmic haze she felt her entire weight shift, and then become weightless as her body finally freed itself from its confines. Then gravity reasserted itself and she crashed into the ground below, landing ass first and her body following behind it. Just as her head lightly tapped the floor she felt a solid lump hit her square in the pelvis, as Lynn lost her own balance and fell onto her.
Lucy groaned, adrenaline and orgasm finally wearing away and being replaced with dull pain. She looked down at the source on her pelvis, just as Lynn pulled herself up. The two of them locked eyes for a brief moment, one of Lucy's eyes exposed. She shot upright, her hair falling back to its rightful place, her face flushed red with embarrassment.
Lynn smiled, pulling herself upright and wiping her chin. "Heh, I don't think I've seen your eyes in years."
"Sigh…" She said, picking up her jeans and underwear. "You weren't supposed to ever see them again."
"They're nice, though." Lynn replied softly. "And hey, now you're no longer stuck."
"All it took was destroying any chance of avoiding eternal torment."
"Ah, don't be such a sourpuss, Luce." Lynn grinned, pulling herself upright. She offered a hand to Lucy, who accepted it, pulling herself up to her full height, a solid head taller than Lynn. "Plus, you enjoyed yourself, didn't you?"
"... Yes, I did." Lucy held one of her arms.
"Anyway," Lynn started, moving to her side of the room and pulling out a large duffel bag from the corner. "I came in here to grab this. Catch ya later, Lucy, don't get stuck in the vents again."
Lucy waved to her as she left, the door slamming hard behind Lynn.
Looking back at the open vent, she sighed.
She almost wanted to do it again.