Denver woke up as soon as Jackie did, feeling the commotion of her body shifting out of its slumber. Watching as she removed the tube from her butt, he only got a few moments of relative peace before discovering that she’d brought along her butt plug from his time with her over New Year’s. Within seconds of her lifting the gas mask away from his body, she dropped him into the eerily familiar anal cage—without even saying good morning to him—and then inserted him up her rear before getting dressed.
The ride back to Jackie’s apartment was a long and uncomfortable one, of course. Confined within the cramped chambers of his own sister’s asshole, he couldn’t even try to fall back asleep, since the rumbling of her car was enough to keep his tiny body constantly vibrating. He hated that he recognized the smell of Jackie’s insides. It was a humiliating thing, for someone to know what the inside of a rectum was like, nevermind their monolithic little sister’s.
When they got back to her place, she removed him again and dumped his body into a weird looking glass box that was sitting near her bedroom window. While she went to put her things away and make breakfast for herself, he looked around his new enclosure, assuming it’d be “home” for as long as she was going to be keeping him again. On one side of the box was what looked like some kind of air filter, some kind of ventilation-related engineering that made up the entirety of the wall. The other three sides were all just made of glass.
She came back into the room around 20 minutes later, having given herself enough time to to have some breakfast. He didn’t bother trying to fight her as she reached in for his body and laid him down on her desk, and she didn’t bother telling him what she was up to. The air was just silent; strained for Denver, but perfectly pleasant and fine for Jackie. She lightly hummed a song while binding his wrists together, and then tied him to a hook in the center of a glass square that Denver assumed was the box’s lid.
Once her brother was secured, Jackie adjusted the box’s position so that it was a few inches from the window, where the day’s sun was already shining in. As she lifted the box’s cover, about to set it on top, Denver piped up with a concern he had: “Are you purposefully putting it in the sun, or could you just keep me in the shade?”
“It’s on purpose,” she answered matter-of-factly, and slid the lid into place over the glass cube—the edges were made of a soft plastic, ensuring that the box would have an airtight seal. As she stood back, she considered that her brother nearly looked like a decoration, hanging right in the center of his new little prison. His body resembled a prisoner from a movie; hanging naked from his wrists, suspended in mid-air. He wasn’t beaten and bruised like in movies though, but he’d still be getting tortured all the same.
“The window’s facing south,” she told him, “so you’ll get to hang in direct sunlight for most of the day.” Denver groaned, already feeling the searing effects of the 100 degree day. “But lucky for you, you’ll have a kind of air conditioner! That’s what that mechanical box on the side is. I didn’t know how long it’d take you to slip up, but I was pretty confident you were gonna eventually. So I had this thing custom made.” She leaned over, and her giant face looked down on him with a disappointed look. “Honestly, I was really hoping you wouldn’t. And like, I still figured you would… but I didn’t expect you to nearly spill your guts to Mom and Dad. Pissing me off like our last three times together would be one thing, but this time you actually jeopardized our secret—and my safety too.”
Jackie stood back up and sighed, opening her desk drawer and pulling out a plastic tube like what she’d used last night, except this one was considerably longer. “Anyways, like I was saying, the part on the side acts like an AC sort of… although the air’s not gonna be super fresh,” she remarked with a giggle. He turned to watch over his shoulder as she screwed one end of the tube into the top of the mechanism, and then took her pants off before inserting the other end into her butt like the night before. Once she had, she sighed with relief, and immediately let loose an overlong, bubbling barrage of gas. With her hands on her hips, she smiled and looked over at Denver’s box with anticipation. The tube was significantly longer than the other one—at least fifteen feet—so it took a few moments to travel through, but eventually it reached Denver’s box. One second, there was silent stillness, and the next, a warm breeze was blowing against Denver, strong enough to cause his hanging body to lightly swing back and forth. “Hope you like that organic air conditioning,” Jackie teased. The smell was raw and apparent, and she laughed at the image her brother getting blown about by her noxious gas.
“So!” his sister announced, now that he’d been introduced to her devious mechanism. “What’s so special about that machine is that it works as a filter to separate oxygen from my farts, so there’s a greater concentration of hydrogen sulfide when it blows in your face—that’s what make them stink in the first place. So hopefully that one smelled shittier than normal. Anyways, there’s also an intake part on the bottom, that one filters in all the carbon dioxide and some nitrogen, but makes sure the smelly stuff and oxygen stays put. And then just to make sure I don’t accidentally kill you, an air monitor tests the oxygen levels in the air to make sure they stay around 20%. Cuz too much oxygen will burn your lungs, apparently. And obviously if you don’t get enough, you’ll die.
“Sooooooo, every night I’m gonna hook my ass up to your little machine like last night. And if all goes according to plan, then your little prison should get stinkier and stinkier as time goes on. Like, apparently less than 1% of a normal fart is made up of the smelly stuff, so it’s gonna take awhile.”
She then pressed a button on the machine, and Denver heard the machine start vacuuming the air, and within seconds, he was struggling to breathe. Jackie lifted the lid off his enclosure, and he gasped in relief at the fresh air as it flooded his lungs. “And whenever I take you out, I can make sure it sucks in all the air and temporarily replaces it with oxygen again, to make sure I don’t lose my progress.” She grinned, proud of how detailed her mischievous plan was. “Pretty tricky, right?”
Denver was silent for a moment, thinking about what she’d said. Her plan to increase the concentration of her farts over time. The other three times she’d shrunk him down, he knew how long she’d have him for, but considering how upset she was this time after he almost revealed the truth to their parents, he expected to be toyed with even more. “How long is my punishment gonna be this time?” he asked.
Jackie looked at him with pity; “Wait, you didn’t realize yet? I figured it was kinda implied based on what I said.” She sighed, looking genuinely sorry for him. “I can’t risk letting you regrow again. If you told Mom or Dad even more than you already did, or the cops, or really almost anyone else… my life would be ruined. I’d probably go to jail, I’d never talk with Mom or Dad again cuz they’d be disgusted with me or hate me or disown me. So this is the only solution. You’re gonna have to stay shrunken for… well, for the rest of your life.”
Denver was stunned by her words. He wished she was joking, but it pained him how much sense she was actually making, which is why he knew she was telling the truth. She was right; he’d probably slip up again, and not just in a way that annoyed her like before, but in a way that would ruin her life. It was either his life or hers, and naturally, she was just choosing hers.
“That’s why the machine is important,” she explained, putting her tiny brother back into his glass prison. “Having to keep farting on you, literally multiple times a day forever? And if I slip up just once, you’d regrow again. So that’s why I’m hoping that if you have to breathe in my gas for long enough and at a high enough concentration, it’ll become a part of you. Like a smoker’s lungs are stained with tar, right? Well, I want your lungs to be stained and coated with my farts—permanently.”