Jen eyes slowly opened as she woke up to the sounds of birds chirping. She had just had a long pleasant sleep and felt ready to start the day. Sitting up on the edge of her bed, she could feel her guts start to awaken. The groggy girl ripped a massive loud fart into her mattress.

"Hah..." she sighed with relief. "That felt good."

Jen didn't mind cutting one loose like that when no one was around. It was embarrassing in public, but at home the smell of her own brand didn't bother her much. Her armpits were another story. She lifted an arm up and could smell the pungent caked-in sweat from the previous day.

"Hmm, no good. Time for a shower." she said. With that, she was up.

----

Back in Mark's reversed time he was standing in Jen's panties, quivering in fear under the gigantic butt that was standing over him. Within a few seconds should would pull up the dirty panties and pull him back in her ass.

"I didn't see this coming! Can I make it out of here? Do I have enough time?! If I jump off the panties when she's pulling them up will I fall to my death?"

He was overthinking it. Too scared to actually take any action, Mark just stood there and let the girl put on her undergarment. The cloth elevator zoomed up her delicious legs, taking the tiny boy with them. The daunting ass grew bigger and bigger in his view but he couldn't look away. Twin buns filled his vision until he was plunged between them, thrown yet again into darkness.

Her panties returned to their previous state, wedged far up her butt. After a long night's sleep her ass had devoured those panties like a hungry beast. Mark was lodged in the center of her thick cheeks, surrounded by tons of flesh on either side. They rolled up and down as the giant girl walked backwards to her bedroom, grinding the boy into nothingness. With every step she made her plump butt wobbled, crushing Mark inside while he cursed in pain.

"Dammit! How could this happen! I planned out everything! I was out! OH GOD WHAT IS THAT?!"

His nostrils flared up as her panties began to smell. The stench of her ass was awful! Then he felt a quick rush of vertigo followed by the immense butt flesh collapsing onto his small form. She had sat down on her bed. A small rumble built up into a raging storm around him. Gusts of heavy smell emerged from the mattress and flew in between her butt cheeks as the ass unripped its massive fart. Rolling thunderous waves of gas made her twin cheeks vibrate on the bed, searing blasts of flatus concentrated on Mark's spot. Her ass began to suck him up like before, but not before her giant cheeks had finished chewing him like a piece of gum. The sound of her inverse release was horrifying, it drowned out the tiny boy's screams with ease. Finally her ass calmed down and Mark was left farther up her butt crack, much closer to her rancid hole.

Then... silence. The giantess had laid down and returned to her state of sleep and things for Mark got real boring, real quick. He was flattened under the pressure of the girl's ass halves and was unable to escape, let alone move. Time crawled by in reverse slowly, all he could do was lie there and breath in the smell of her butt flesh. It wasn't great, but at this point he was used to worse.

Hours went by. Jen was lying on her side, her cute butt cheeks looked like two pale hamburger buns. Deep inside, sandwiched between them was Mark, the "meat" of this perverse burger. He reflected on his situation. Even though he was in a shitty situation, at least the girl he was with was hot. It could have been much worse. An old fat hag could have walked into that unisex bathroom, or even worse... a man. Mark shuddered at that though.

Jen shuddered too, only it was her butt that shuddered. Another deafening blast of gas pummeled Mark's body, sending him further inside the beastly booty. The sideways rumps gobbled him up with the fart and brought him deeper with the stink. Unknown to the both of them, Jen was prone to night farts, and would expel lots of gas while she slumbered.

Throughout the night that was what he had to deal with. Hours of nothing and then roaring chaotic farts. Sometimes they were loud and pulled him in deep. Other times she had rolled on her back and the weight of her cheeks held him in place. One time an especially big fart woke her up. She sat up still half-asleep, cutely asking "Anyone there?" while Mark yelled and screamed inside her butt. Hearing none of it, she went back to sleep.

The giantess slept on calmly, unaware that her ass was eating a boy yet again. Each bout of gas pulled him in a bit more. It was like the monstrous butt was giving him a taste test before swallowing him whole. Licks of gas rolled him around in the beasts "mouth" savoring his body until it felt like the time was right. After each fart went away Mark could hear the bowels gurgle as if the ass was getting hungrier.

Finally one of her butt blasts had brought him to his destination, her anus. The puckered hole eagerly gulped the last of her fart and pulled Mark with it, giving him a light kiss on the face. Mark recoiled away from the nasty asshole, spitting the taste of it out of his mouth. The wrinkly maw quivered and flexed, like it could detect his presence. Mark tried to stay away from it as much as possible, the heat coming off of it was enough to make him sweat. The only thing was he had no place to run to. Down in the core of this girl's ass crack it was just him and the slimy gross anus.

Another agonizing hour later is when it happened. Mark heard a muffled rush of wind from outside the colossal walls of butt flesh behind him. The pocket of air wormed through her bubbly cheeks and converged at a single point in her crack. The air pocket burst open on Mark like a shotgun blast, all the heat and smell engulfed him at once. The greedy anus convulsed and spread open to let the fart through and suck Mark inside.

Desperately he clutched the rim of the vibrating shithole, using all his strength to stop it from sucking him inside and eating him. The anus shrank around his head, still farting while it suckled on his skull. Mark shouted in pain as the rumbling wrinkles tried to rip his head from his neck. It wasn't open wide enough to get a grip on his shoulders. Mark's lower body was squirming and dangling as he tried to wrench himself loose. The hot fart popped inside and the butthole squeezed shut on his head. A slimy anus wrinkle had wedged inside Mark's mouth and now he couldn't breathe. Terrified, the boy screamed for help.

That scream was important. The vibrations sent tingles of pleasure back to Jen's subconscious mind and her body. Mark didn't realize that his cries were turning her on. He had forgot how his actions had an effect on the past. Since time was going backwards, if he turned on the giant girl now she would need a reason for feeling pleasure in the past. Mark pulled his mouth out from the asshole but the rest of his head was still stuck inside. Not that it mattered, it was too late. His careless actions had created a new event on his timeline!

----

Jen relaxed and put her panties back on. Finishing masturbating in bed for the night, she rested her head on the pillow and let her tingles of pleasure put her back to sleep.

----

Mark would slowly learn of what was coming. The ass would begin to get hotter around him. Her blood would slowly start pumping faster, creating loud thumps in her puckered anus. The erotic hole would start to spasm and loosen, letting Mark's head free. He could see and feel the dried sweat on her body turn into liquid again, coating his body in juices. Beyond that he couldn't see it, but her whole body was beginning to glisten in sweat. Her nipples slowly stiffened and her heart raced. The girl's body was returning to a state of heightened arousal, one achieved by her own masturbation. And with the way her asshole was opening up it looked like that was the hole she used to cum.

A blinding surge of light came to Mark as the girl's panties were removed and her ass was spread. The shithole behind him drooled with lust as a blurry thing approached Mark from the outside world. It was ready to plunge him in a hell unlike he had ever seen. What was it?