Liz's eyes widened as she felt that familiar tingling sensation building up in her massive rump yet again, only now it was more like a quaking rumble, sending ripples through her beachball sized cheeks. "Well, so much for wearing a skirt, " she thought before letting out a soft moan as her monstrous ass began to bloat up even bigger. She plopped back onto her double bed, which groaned and creaked under her building weight.
"I don't care," she muttered looking at her huge swells from over her shoulder, reaching back and grasping at what little she could of them, "I want you even bigger, my beautiful, gimungous monster butt!" Her thighs and hips widened as well, legs lengthening a bit, even, but her rear cleavage was the star of the show: It swelled up to cover all of her bed, the growth not stopping until her butt-flesh was overflowing and bulging downward towards the bedroom carpet Liz was completely in love with her gigantic ass; it just felt better the bigger it got.
As the growth spurt slowed to a halt, she pulled her fingers from her sopping, enlarged pussy, bringing them up to her face for a deep sniff, and then a lick. Liz stood up from the bed with a wet, sluch-sound--the blankets, sheets, and mattress now soaked almost completely by her juices.
"I'm....such a BIG girl, now!" she giggled, giving her outrageous rump a loving, prideful smack. "I could fit, like, a whole other person in my cheeks!" She then emitted a high-pitched "eep" as she heard a knock at her door--it was her brother: "You missed your bus again, Liz! Mom and Dad already left, so....I gotta drive you 'n now I'm gonna be late, too! Get your flat ass in gear, already!"
A. Liz convinces her brother that she's too sick to go to school today, and he leaves his little sister to enjoy her big, new, growing body for the day.
B. He barges into her room, and is quickly sat on by his huge little sister. "It's not so 'flat' anymore, is it?"
C. Liz fashions a skirt out of her bedsheets--she's gotta go to school and show off all this buttflesh!