As class went on Nikki shifted her huge ass around in her chair. She was trying to smear her gross anus all over Mark, still under the assumption that he was an inch tall and that she was just playing around with him. In reality however, Mark was much much smaller to the point where just one of the wrinkles of her anus dwarfed him in size. Nikki only wiggled her ass around slightly, as not to draw attention to herself, but her small movements were akin to a world-shifting event from Mark's perspective. The gigantic stuffy anus dragged him from side to side, steamrolling his tiny powerless body. None of his weak screams were loud enough to penetrate the thick barrier that was Nikki's seated buns.

Even by normal-sized people's standards Nikki's teenage ass was huge. Her plump booty and thighs were big enough to spill over the sides of her school chair. She bit her lip imagining Mark being swallowed up and helpless inside her crack. Using her big butt to dominate her friend felt so good, it excited her that she was doing this in the middle of class.

Meanwhile Mark was fighting a losing battle with her anus. The oily pucker was pummeling him into the back of Nikki's panties, right up against the hard surface of her chair. Her disgusting wrinkles tumbled over top of his body, each time threatening to pinch down on one of his limbs. Mark was terrified at the possibility of her anus grabbing hold of him, he was certain that if it did it would completely gobble him whole. As time went on he could feel Nikki's muscles clench and her anus folds contract on him a few times. She was clearly enjoying this feeling. Mark shouted in pain and frustration. Just knowing that she was getting off on smothering him in her ass was awful, especially when she had no idea of how much danger he was really in.

She couldn't even pay attention to the lesson, this was just too much fun. It was decided then that today would be dedicated to playing with Mark in her ass. As she daydreamed of what she could do next with her rump, her stomach growled. That gave Nikki an idea, her lips curled into a mischievous smile.

Mark heard a distant ominous rumbling sound. Suddenly her ass stopped moving. A bright light then blinded him temporarily as one of her tremendous ass cheeks lifted skywards. The light was flooding in from the outside world, through her panties. At first he thought she was getting up from her seat and his torture was over but then his heart sank as he realized she was just lifting one leg. If she wasn't getting up it could only mean one thing: She was about to blast him with a fart.

Mark ran as fast as he could, making little ground in the vast expanse of her panties. The fat meaty buns towered above him, like a slanted ceiling as high as the clouds. He couldn't go far, the underwear eventually curved upwards with the ass, forming a impassible net of cloth. He gripped the strands of fabric walling him inside, the criss-crossed weave looked like prison bars to him. Outside he could see the person sitting next to Nikki, his friend Allyson. He yelled as loud as he possibly could to get her attention but it was no use. There was no way she ever could have heard him, he was just too small.

Falling to his knees, Mark felt hopeless. There was no way out. He turned around to see Nikki's anus peeking out behind her cheeks. It grew larger and was puckering, just about ready to fire.

"Nikki.... Noooo..." Mark sobbed.

Her ass let out a short sharp fart with big squelching noise. It was a wet one. A big gob of her anal slime shot out from her asshole, landing on top of Mark with a splat. He had no way to avoid it, it was bigger than a house. For a moment he panicked, wondering what the hell had just happened. He was encased in the middle of the juicy gob and stuck to the bottom of Nikki's panties. He couldn't even see through the slime, it was too murky with brownish traces of her anal filth. The whole thing smelled horrible and clogged up not just his nose, but every crevice of his body. Completely encased in the glob Mark had nowhere to move and nothing to breathe.

Nikki's eyes widened when she felt how wet her panties had just become. She went too far. She was expecting a hot silent but deadly fart, not a wet sloppy one. Worst of all the whole class heard it and turned to look at her. Her face grew red with embarrassment and she timidly sat her ass back down in the chair. Mark felt the world go dark as her ass came crashing down on top of him again. Her butt shifted and the gob of wet sticky juices was wedged right between her two cheeks.

Mark remembered how Nikki's anus had an overabundance of slime inside it and how he used that to escape. Her rectum must have been backed up with tons of sticky juices and her fart must have blasted some of them out. The tiny boy tried to escape only to realize the cold hard reality: he couldn't move an inch. With all the strength in his muscles he couldn't get his arms or legs to go. The sticky mucus was just too thick. His body craved for him to breathe some air but he was encased in nothing but gross anal slime. He struggled what little he could, trapped in the sticky pool at the bottom of Nikki's panties, with her huge fat ass seated on top of him.

He didn't want to die here, but with every passing second it seemed like he was doomed to. It awful, getting killed by the disgusting gunk that lined the walls of a girl's ass tunnel. Her hot anal juices that would normally ease her shits along were being used to end a life, unaware to their owner. Mark would have rather been crushed or gassed to death than this, it was just too scary and pitiful. Nikki has no idea that under her butt her friend was struggling desperately or his last breath, she had gone back to doing her work.

Mark's lungs burned for air, instincts fighting over his common sense not to breathe. He tried to get a small bubble, any pocket of air he could find inside the frothy mixture, but all he got was a mouthful of slime pouring into his lungs. The hot gooey juices burned his mouth with the taste of her shit, causing his heart rate to accelerate. He began to drown in her slime, his mind screaming for Nikki to save him. Her finger, another fart, anything to get him out of this shit-stained gob of death. Mark twitched and choked on her mucus slowly watching his whole world go dark...

Nikki checked her panties after class, disposing of the gob in a tissue and flushing it down the toilet. It puzzled her to the whereabouts of her friend until she realized she hadn't actually seen him since she put him in her ass back in her bedroom. He must have escaped there, right? She put her panties back on and returned to classes, determined to find Mark in her room when she came home. She never did.