Nikki was starting to worry. Maybe she actually couldn't feel Mark in her panties because he was too small. Quickly digging into her school bag Nikki looked at the portal device's last settings. Time slow down? Either way, when she saw the size she shrunk Mark down to her heart sank. She wasn't sure how small he was, but a decimal point with that many zeroes after it couldn't be good.

The bell rang and Nikki shot up from her seat. Charging her way through the crowd, she made a mad dash to the nearest ladies washroom. She needed to check if Mark was safe! Nikki slammed the stall door closed and pulled down her underwear for a panty check. Her huge bare ass sank into the toilet seat as she examined the panties, bringing them as close to her face as possible. She gulped nervously. There was no sign of Mark.

Was he stuck in her ass crack? Or even deeper? Without a mirror Nikki had no way of checking her plump behind, and if she waited until she got home Mark could already be dead! As Nikki panicked, her insides began to churn. Her ass, feeling the familiar touch of the toilet seat, started to growl. Nikki felt a fart coming on, and got an idea. As gross as it was, if Mark was stuck up her booty, maybe she could blast him out with a fart. Her gassy winds would probably be enough to peel him off the sides of her butt cheeks, or even her asshole, right? She made a face and grunted, pushing the gas along...

----

When Nikki got up from her seat Mark's entire world turned over. Her smothering anal muscles began to relax, and all the anal juices lining her bowels started dripping downwards from gravity. Mark, still immobile within the thick slime, was just about to give in to the embrace of death when his head popped inside a frothy stink bubble. Miraculously finding somewhere to breathe in such a place, the shrunken boy coughed up gobs of slime and took his first heave of air in what felt like forever. It smelled like pure shit but he didn't care, he was still alive.

As the giant girl ran to the washroom her insides shook violently. The sticky slime had begun to form a pool near her exit hole, and was now sloshing around from her movements. Mark's minuscule body was stirred around in the flow of juices, and was pulled away from the bubble that was keeping him alive. Once again he was caught in a chaotic whirlpool of girl grease, left to drown. A thunderous quake rocked his body as Nikki sat down on the toilet seat. Everything went still for a few seconds as Mark's lungs screamed for air.

Eventually something screamed back. A low organic groan echoed through Nikki's bowels. The walls of her ass began to quiver. Still trapped under the heavy goo, Mark felt strong rumbles travel his way. Enormous bubbles of gas filled above the pool of slime, bloating the colon. The pressure built and built until the ass muscles squeezed down and forced it all out. Nikki's ass farted with a wet roar, blasting Mark downwards with the force of a rocket launch.

With a splash he hit the water, along with an eruption of Nikki's anal juices. All the slime that had been pooling inside her bowels sprayed out at once, along with the fermented gases that came from within. The gross glob Mark was encased in dissolved in the toilet water, finally freeing him. He tread water and felt cool air fill his lungs. It was so great! No more blistering heat, no more awful smell! He was finally free of Nikki's ass! Never before had Mark been so happy to have Nikki fart on him. He could see light again. Up above he was greeted by the girl's backside, and her spread drooling anus. Now he just needed her to see him.

Nikki's shoulders tensed as she felt how wet her fart was coming out. Was her ass really that wet? She could feel the remainder of runny slime dripping from her anus. Later she would need to wipe her butt cheeks with toilet paper to clean up. Before that though, was Mark okay? She needed to check the toilet for his shrunken body.

Getting off the seat Nikki turned around to place her head above to toilet. She recoiled a bit from her own smell. Man, her gas was bad today. Fanning it away she leaned closer, inspecting the water for any signs of her friend. He was below, waving his arms and yelling up to her giant face. But was he too small for her to see? Her next words sealed his fate...