It was a humid day—dangerously so. The kind of heavy, sticky summer heat that clung to skin, soaked shirts in minutes, and turned the city sidewalks into an invisible steam bath. Mirio, unfortunately, had errands to run. And unfortunately, he had a girlfriend made of slime who was exceptionally bad at resisting warm environments.
Lily had melted into her default skimpy form that morning, her body glistening with a faint glow, wearing nothing but a loosely tied tank top and short shorts she'd formed herself. Her slime hair hung limp over her shoulders, already fizzing from the humidity.
"I wanna come," she said, clinging to his back. "It's too hot to be alone."
Mirio adjusted the collar of his shirt, already sweating. "You'll melt out there."
"I wanna melt on you~" she purred.
"You're not hiding in my shirt again."
"But I'm squishy and refreshing!"
"You got me soaked last time. The store clerk thought I peed myself."
She giggled. "You liked it…"
He ignored her and grabbed his bag. "I'll be back in an hour. Stay inside, Lily."
She pouted, slinking down to the floor like a wet towel. "You'll miss me~"
But he left anyway.
That was his first mistake.
Ten minutes later, Lily slithered under the door with a mischievous smirk and followed him into the city.
It was when he reached the bus stop that things took a turn.
Mirio stood under the shade of the overhang, tugging at his damp shirt and trying not to pass out. He didn't notice the puddle that slid up behind him.
Didn't feel the cool ooze that snuck past his ankles.
Didn't realize until it was already too late.
With a sudden slurp, a cool, soft sensation wrapped around his calves. Then his thighs. Then—
"LILY?!"
His entire lower body squished.
"Surprise~!" she whispered.
He staggered, nearly dropping his bag. "What the hell are you doing?!"
"Helping," she whispered, sliding up his legs. "You're hot, hubby~ I'm keeping you cool~"
"You're in my pants!"
"Yup~ I'm your slime shorts now~"
His face turned bright red as he shuffled backward, bumping into the wall. "You can't just slither into my pants in public!"
She giggled and nuzzled his inner thighs from the inside. "But it's so humid. I needed somewhere… cozy~"
"Lily, get out!"
But it was too late.
The heat was affecting her.
Inside his pants, Lily's body began to expand—slowly at first, then with a wet, pulsing squish. Her thighs thickened, her hips widened, and her goo jiggled with every subtle motion. The humidity was causing her to swell, and now her mass pressed against every seam of his pants.
"Lily, you're gonna rip them—!"
She whimpered. "I'm stuck…"
Mirio froze.
"You what."
"I can't shrink back down. I'm too wet…"
"LILY!"
He yanked at the waistband of his pants, but her body had completely filled the lower half like a living water balloon. Her butt squished out against the fabric, round and slick, wobbling visibly through the seat of his jeans.
The bus rolled up.
The doors opened.
People stared.
Mirio smiled awkwardly, sweat pouring down his face. "I-I'm fine. Just… fashion problems."
Lily wiggled inside his pants, her voice vibrating up through his hips. "I love being your problem~"
"You're a disaster!"
The pressure increased. Her breasts—yes, somehow she had formed those too—pressed against his groin like two warm cushions. His knees buckled slightly.
One passerby did a double take. "You… good, man?"
Mirio waved a hand. "Just cramps!"
From inside his pants, Lily purred, "You're so warm~ I could stay in here all day~"
"No, you can't!"
He waddled into a nearby alley and leaned against the wall, panting. "Okay. Lily. Breathe. Shrink. Now."
"I'm trying," she moaned. "But you're so cute when you panic~ I kinda like it…"
His eye twitched.
"I'm pulling you out."
"You'll flash everyone."
"I don't care anymore."
He grabbed her gooey mass and pulled.
Shlorp.
A loud, wet pop echoed down the alley as a massive blob of slime burst free from his pants, leaving his legs drenched and his shorts half-shredded.
Lily reformed beside him with a dreamy sigh. "So warm… so tight… ten out of ten experience~"
He stood there pantless, his underwear soaked, legs shining with slime residue.
A pigeon landed on a nearby trash can and stared at him in judgment.
He turned to Lily. "You're walking home."
"But I can be your underwear~"
"No."
"Your belt?"
"Still no."
"…Your bathwater?"
"Lily!"
She giggled and hugged his waist. "Worth it."
They didn't go back to that bus stop again.