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Frisks back pocket
Fandom: Undertale
Created: 6/25/2026
Tags
AU (Alternate Universe)Slice of LifeHumorPWP (Plot? What Plot?)Curtainfic / Domestic StoryCanon SettingCharacter StudyBody HorrorPurple Prose
The Greenhouse Effect
The front door of the surface house slammed shut with a heavy thud, echoing through the quiet hallway. Frisk didn’t bother kicking off his sneakers, instead scuffing his way toward the living room with the heavy, rhythmic gait of someone who had spent far too much time trekking through the damp humidity of the Underground. He was a teenager now, and with that growth came a certain lack of concern for hygiene that Toriel frequently complained about. His striped shirt was stained with sweat, clinging to his back in dark patches, and a pervasive, earthy musk followed him like a cloud.
"I’m home!" Frisk called out, his voice cracking slightly.
There was no answer. Toriel was likely at the school, and Sans was probably off taking a "legally mandated" nap at one of his many stations. Frisk sighed, his shoulders slumping. He felt heavy, his stomach churning with the remnants of a poorly thought-out lunch consisting of Glamburgers and Starfaits.
In the chaotic rush of his jog back from the mountain's base, Frisk had completely forgotten about the passenger tucked away in his clothes. Earlier that afternoon, he had spotted a tiny, sentient sprout—a miniature Venus Flytrap-like monster no bigger than a finger—shivering in a patch of dying soil. Fearing the little creature wouldn't survive the night, Frisk had picked it up. Having no pockets in his worn-out shorts, he had hastily tucked the tiny monster into the waistband of his underwear for safekeeping.
Now, Venus was wedged firmly in the dark, humid crevice of Frisk’s backside. The little monster was pinned flat against the teen’s sweaty skin, its tiny leafy mouth pressed directly against the fabric of his boxers.
Frisk groaned, rubbing his belly. "Ugh, my stomach is killing me."
He flopped onto the overstuffed sofa, landing with a forceful *whump*. The impact sent a shockwave through the cushions, and more importantly, drove Venus deeper into the narrow space where he was trapped. The little monster let out a silent, muffled protest as the sheer weight of the teenager crushed him against the leather of the couch.
Frisk didn't notice. He wiggled his hips, trying to find a comfortable position, unknowingly grinding his backside—and the tiny monster trapped within—into the cushions. Each shift of his weight was a tectonic shift for Venus, who was currently being smothered by the damp, salt-scented heat of Frisk’s skin.
"Finally," Frisk muttered, reaching for the TV remote. "Time to do absolutely nothing."
He slumped back, his posture becoming a lazy, sprawling mess. As he relaxed, his muscles loosened, and the digestive consequences of the Glamburgers began to manifest. A low, gurgling sound erupted from his gut, audible even over the hum of the refrigerator in the kitchen.
Frisk let out a long, relieved sigh as he felt the first wave of pressure move down. He didn't hold back. With a dull, muffled *pfft*, a cloud of thick, warm gas escaped, trapped instantly by the tight confines of his denim and the heavy upholstery of the sofa.
For Venus, it was a catastrophe. The tiny monster was positioned at ground zero. As Frisk shifted again, grinding his weight down to ease the cramp in his stomach, the gas was forced directly into the small space where Venus was pinned. The little plant-monster had no choice; its biology required it to breathe, and the only atmosphere available was the pungent, humid air being pumped out by the teenager.
"Whoops," Frisk chuckled to himself, feeling a bit of the Bloat subside. "Guess that’s what I get for eating monster food so fast."
He shifted his weight to the left, leaning on one buttock to reach for a bag of chips on the coffee table. This movement created a momentary vacuum before slamming shut again, further mashing Venus against the sweaty fabric. The little monster’s face was buried deep, its leafy appendages flailing weakly against the overwhelming pressure of Frisk’s lazy, unwashed body.
Another gurgle rolled through Frisk’s abdomen. He leaned back, spreading his legs and sinking deeper into the cushions. The heat in his pants was rising, a combination of body heat, sweat, and the stagnant air of his own making.
"Man, I really need a shower," Frisk said aloud, though he made no move to get up. "Maybe after this episode."
He let out another long, rolling burst of gas, this one louder and more sustained than the last. The vibration rattled through the couch cushions. Because of the way he was sitting, the gas had nowhere to go but to circulate within the fabric of his clothes, thick and inescapable. Venus was submerged in it, the tiny creature’s senses overwhelmed by the sheer, concentrated essence of Frisk’s teenage lethargy.
Frisk reached down and scratched his stomach, his hand disappearing under his shirt. He was completely oblivious to the struggle happening inches below his spine. To him, he was just a tired kid enjoying the comforts of home. To Venus, he was a giant, unmoving mountain of heat and smog.
"I wonder where I put that little plant guy," Frisk mused, blinking at the television screen. He patted his basic pockets, which were empty. "I hope he didn't fall out while I was running. That would suck."
He shifted again, his heavy denim rubbing harshly against the spot where Venus was wedged. The grinding motion was relentless. Frisk was trying to scratch an itch by wiggling against the couch, using the friction to satisfy the sensation. Every move pressed the tiny, gasping monster harder into the "greenhouse" of his underwear.
"Ah, that’s the spot," Frisk sighed, his eyes half-closing.
The air in the living room was starting to grow stale, but the micro-climate inside Frisk’s clothes was far worse. It was a swampy, humid environment, fueled by the sweat of a long jog and the constant release of digestive pressure. Frisk, being a teenager who had spent years living in dusty caves and damp marshes, was largely nose-blind to his own scent. He simply felt cozy.
He let out one more heavy, vibrating sigh of gas, the kind that came with total muscular relaxation. He was practically melting into the sofa now, his weight fully distributed in a way that sealed Venus into a pocket of pure, unfiltered musk.
"I'll look for him in a minute," Frisk whispered to himself, his voice trailing off as his head lolled to the side. "Just... five more minutes..."
Within moments, the teenager was snoring softly, his chest rising and falling in a slow rhythm. With every breath he took, his body shifted slightly, maintaining the crushing pressure on the tiny stowaway. Venus remained trapped in the dark, a silent witness to the pungent reality of the Savior of the Underground’s lazy afternoon.
The sun began to set outside, casting long shadows across the living room, but on the couch, nothing moved. Frisk remained slumped and gassy, perfectly content in his own filth, while the little monster in his pants could only wait for the giant to finally wake up and remember he wasn't alone.
"I’m home!" Frisk called out, his voice cracking slightly.
There was no answer. Toriel was likely at the school, and Sans was probably off taking a "legally mandated" nap at one of his many stations. Frisk sighed, his shoulders slumping. He felt heavy, his stomach churning with the remnants of a poorly thought-out lunch consisting of Glamburgers and Starfaits.
In the chaotic rush of his jog back from the mountain's base, Frisk had completely forgotten about the passenger tucked away in his clothes. Earlier that afternoon, he had spotted a tiny, sentient sprout—a miniature Venus Flytrap-like monster no bigger than a finger—shivering in a patch of dying soil. Fearing the little creature wouldn't survive the night, Frisk had picked it up. Having no pockets in his worn-out shorts, he had hastily tucked the tiny monster into the waistband of his underwear for safekeeping.
Now, Venus was wedged firmly in the dark, humid crevice of Frisk’s backside. The little monster was pinned flat against the teen’s sweaty skin, its tiny leafy mouth pressed directly against the fabric of his boxers.
Frisk groaned, rubbing his belly. "Ugh, my stomach is killing me."
He flopped onto the overstuffed sofa, landing with a forceful *whump*. The impact sent a shockwave through the cushions, and more importantly, drove Venus deeper into the narrow space where he was trapped. The little monster let out a silent, muffled protest as the sheer weight of the teenager crushed him against the leather of the couch.
Frisk didn't notice. He wiggled his hips, trying to find a comfortable position, unknowingly grinding his backside—and the tiny monster trapped within—into the cushions. Each shift of his weight was a tectonic shift for Venus, who was currently being smothered by the damp, salt-scented heat of Frisk’s skin.
"Finally," Frisk muttered, reaching for the TV remote. "Time to do absolutely nothing."
He slumped back, his posture becoming a lazy, sprawling mess. As he relaxed, his muscles loosened, and the digestive consequences of the Glamburgers began to manifest. A low, gurgling sound erupted from his gut, audible even over the hum of the refrigerator in the kitchen.
Frisk let out a long, relieved sigh as he felt the first wave of pressure move down. He didn't hold back. With a dull, muffled *pfft*, a cloud of thick, warm gas escaped, trapped instantly by the tight confines of his denim and the heavy upholstery of the sofa.
For Venus, it was a catastrophe. The tiny monster was positioned at ground zero. As Frisk shifted again, grinding his weight down to ease the cramp in his stomach, the gas was forced directly into the small space where Venus was pinned. The little plant-monster had no choice; its biology required it to breathe, and the only atmosphere available was the pungent, humid air being pumped out by the teenager.
"Whoops," Frisk chuckled to himself, feeling a bit of the Bloat subside. "Guess that’s what I get for eating monster food so fast."
He shifted his weight to the left, leaning on one buttock to reach for a bag of chips on the coffee table. This movement created a momentary vacuum before slamming shut again, further mashing Venus against the sweaty fabric. The little monster’s face was buried deep, its leafy appendages flailing weakly against the overwhelming pressure of Frisk’s lazy, unwashed body.
Another gurgle rolled through Frisk’s abdomen. He leaned back, spreading his legs and sinking deeper into the cushions. The heat in his pants was rising, a combination of body heat, sweat, and the stagnant air of his own making.
"Man, I really need a shower," Frisk said aloud, though he made no move to get up. "Maybe after this episode."
He let out another long, rolling burst of gas, this one louder and more sustained than the last. The vibration rattled through the couch cushions. Because of the way he was sitting, the gas had nowhere to go but to circulate within the fabric of his clothes, thick and inescapable. Venus was submerged in it, the tiny creature’s senses overwhelmed by the sheer, concentrated essence of Frisk’s teenage lethargy.
Frisk reached down and scratched his stomach, his hand disappearing under his shirt. He was completely oblivious to the struggle happening inches below his spine. To him, he was just a tired kid enjoying the comforts of home. To Venus, he was a giant, unmoving mountain of heat and smog.
"I wonder where I put that little plant guy," Frisk mused, blinking at the television screen. He patted his basic pockets, which were empty. "I hope he didn't fall out while I was running. That would suck."
He shifted again, his heavy denim rubbing harshly against the spot where Venus was wedged. The grinding motion was relentless. Frisk was trying to scratch an itch by wiggling against the couch, using the friction to satisfy the sensation. Every move pressed the tiny, gasping monster harder into the "greenhouse" of his underwear.
"Ah, that’s the spot," Frisk sighed, his eyes half-closing.
The air in the living room was starting to grow stale, but the micro-climate inside Frisk’s clothes was far worse. It was a swampy, humid environment, fueled by the sweat of a long jog and the constant release of digestive pressure. Frisk, being a teenager who had spent years living in dusty caves and damp marshes, was largely nose-blind to his own scent. He simply felt cozy.
He let out one more heavy, vibrating sigh of gas, the kind that came with total muscular relaxation. He was practically melting into the sofa now, his weight fully distributed in a way that sealed Venus into a pocket of pure, unfiltered musk.
"I'll look for him in a minute," Frisk whispered to himself, his voice trailing off as his head lolled to the side. "Just... five more minutes..."
Within moments, the teenager was snoring softly, his chest rising and falling in a slow rhythm. With every breath he took, his body shifted slightly, maintaining the crushing pressure on the tiny stowaway. Venus remained trapped in the dark, a silent witness to the pungent reality of the Savior of the Underground’s lazy afternoon.
The sun began to set outside, casting long shadows across the living room, but on the couch, nothing moved. Frisk remained slumped and gassy, perfectly content in his own filth, while the little monster in his pants could only wait for the giant to finally wake up and remember he wasn't alone.
