As your younger sibling turns around, you were able to see her nice toned butt.
"Hey, Adam! I heard you were into big booties. How's this?" She said, biting her lip as her bottom inflates straight up to having each cheek the size of at least twice the size of beach balls, her body adjusting to be proportional to it as well as the shorts she was wearing.
While you enjoy a big butt, it was your younger sister and you weren't having any of that, until her butt fell on you. Despite its size, it was something that you easily outrun, but some mysterious force kept you still until you right between Amy's cheeks. Shifting around, Amy was quite pleased with herself as you right in front of her pucker and turns her attention to the tv.
"Amy! Get off! You're crushing me!" You shout, though it was quite muffled and you were certain she couldn't hear you or ignored you after some time has passed.
"I can hear you fine. In fact, I can even hear your thoughts," Amy's voice said in your head, slightly confusing you.
"What are you talking about?"
"I became god, if you're wondering what's going on. If you think about it, it should be obvious after everything that happened so far as I made you indestructible despite being shrunk, as you would have dead already," Amy said telepathically, her words being true as you think about it.
Fear seized your body as you realized that your sister could destroy the world on a whim and Amy senses this.
"Hey, I admit I may go crazy over something as awesome as this and may mess with you, but that's too harsh! Taking care of the world is a bit too much for me so I'll stick with messing with you for some minor shit. I'm kind of gassy, so how's this?" Amy said telepathically, her guts gurgling above you before she pushes out a massive fart, jiggling her lower body and you gag on the heavy scent of... roses?
"See? I'm not so bad! Now then, I have a show to watch," Amy said, shifting her butt a bit.
Though you were doubtful of Amy, you were giving her the benefit of the doubt as Amy sat on you and occasionally pass gas directly on you, though she sometimes, made her farts stink, much to your displeasure.
"Show's done, so now I think I'll have you..." Amy said, getting up from the couch.