She looked down at her sleeping older sister. For the last few years she'd been having a nightly dream about how wonderful it would feel to slide down her sister's throat and spend some time in her stomach. Older sis, out of an entirely unnecessary sense of decency and propriety, had said it wasn't right to do it until they were both over the age of 18. Well, as the clock approached midnight, that moment was about to come. She had a feeling her older sister would have come up with some excuse not to do it, but that had been planned for. While her sister was away, the younger sibling had carefully installed an obtrusive PVC frame beneath her sister's sheets and stretched between it a study sheet of latex. Now she tiptoed out of the room and returned with a matching sheet stretched across a flexible gasket. The only difference between the top and bottom sheet was the presence of a small hole, just barely large enough for her sister's face.

With extreme care, she pulled up the edges of the bed's sheets and lowered the gasketed sheet over her sister, affixing it tightly and aligning the hole with her sister's face. Once it was in place, and little sis had taken a moment to thank her luck that her older sibling preferred to sleep face up, she rolled out a vacuum cleaner and hooked it up to a nozzle at one corner of the sandwich of latex sheets. When she was certain all was in readiness, she switched the vacuum on.

Instantly her older sister awoke with a start, but by then it was too late. The tiny bit of air trapped between the sheets was swiftly drawn out, stretching the latex taut across her delectable breasts, midriff, and thoughts. The glossy black surface of the rubber shrink wrapped the recently awoken woman, perfectly outlining her every seductive detail while simultaneously holding her in an unbreakable embrace.

"Wh- huh? What is this?" the groggy older sister asked, struggling but only managing to make the thick rubber creak and stretch slightly.

"It's a vacbed, sis! Guaranteed to hold you nice and tight until someone turns off the vacuum."

"But... but why did you trap me in this contraption."

Younger sister climbed onto the sheet of rubber, letting her body press down against the gloriously slick and warm form of her vacuum packed sibling. She leaned down, coming face to face with her elder and pressing her own luscious breasts down upon the rubber-encased ones below.

"Because I didn't want you to keep me from getting my birthday present."

"But wait, if you- aaaaaah!"

Rather than listen to her stick in the mud of an older sister try to reason her way out of it, she simply inserted four fingers of each hand into her sister's mouth and stretched it open. Pausing briefly to admire the glistening pink maw that would soon be savoring her flavor, she shoved her head inside. The tight, slimy sensation was everything she'd hoped for and more. The tongue, even without meaning to, lapped and slurped against her face and neck, giving her through coating of saliva and a wonderful sample of the tongue's texture.

Sliding her body sensuously along her rubber-bound sister, the younger sibling pulled forced her head deeper, giggling in glee as she felt the tight tunnel of her sister's throat slide across her cheeks and the hardness of teeth flick across her stiff nipples. Once her breasts had plopped inside her sister's mouth, she wriggled and squirmed about, both to make sure her sister got a good taste and to feel that wonderful tongue lick and tease at her areolas. After a minute, though, her rapidly moistening sex demanded it's moment in the spotlight, so she pulled harder. It was a sharp turn that tested her flexibility, but she managed to hook her upper body around and down her sister's esophagus, stretching her head into the tight sack of her stomach. Once she was waist deep, she kicked her legs up in the air and began to kick and buck, letting gravity do the work her arms could no longer do, thanks to being pinned to her sides. It was slow going, but eventually her wide hips slurped inside her sister's mouth, placing her slit in perfect position for a long, lingering taste before a series of rhythmic swallows dragged her down to her knees, then her ankles, and finally sent her feet down the snug tube and into the tightly packed stomach.

Once inside, delighting in the warmth, the gurgling sound, the silky flesh, and the churning massage, she smiled to herself at how wonderfully the plan had come together. The vacbed not only made sure that her sister couldn't stop her from having her long awaited gift, but it squeezed the stomach even more tightly around her, increasing the wonderful pressure of the stomach hug.

~~~

The older sister gasped, both out of exhaustion and arousal as she felt her sister's feet finish their journey. The younger sibling was squirming about, causing an incomparable sort of internal massage that was simply breathtaking. She looked down at her tightly packed stomach. It was now bulged with the form of her sister, creaking and squeaking with a rubbery cacophony every time the younger woman so much as wiggled. The rubber was so tight, she could practically see every detail of her sister's anatomy despite being wrapped in both rubber and flesh.

"Sis!" she called to her sibling-turned-meal.

"Mmmmmhmmmmhmmmhmmmmm!" the younger woman giggled.

"You could have just ASKED!"

"Ymm Mmmmt uvvv sddd nmmmm."

"Okay... fine... So who'd you get to come and turn off the vacuum after you've had your fun?"

"... Nnnn Wnnnn"

"No one?"

"Mmmhmmm."

"So either you figure out how to crawl up my throat, or in a few hours I'm going to poop you out into the vacbed and we'll both be stuck in this contraption until someone comes to see what's making the racket?"

"Mmmhmmm..."

She sighed. "And you didn't even leave me in a position to touch myself while you're squirming in there like the meal you are... Oh well..." She squirmed lightly, confirming she couldn't escape. "Enjoy your birthday, sis."