Without uttering another word, Julie then looked back down at the stone in her hands, concentrating on it as her lips began to silently mouth her request. The stone flickered for a second, indicating that her reality altering wish had been made, and your eyes immediately moved from the shiny lump of rock to your sister's hopeful and enthusiastic face.
"Here we go..." she cooed, her eyes and mouth growing ever wider as she felt something begin to happen to her body, yours soon following suit as the transformation began to take place.
It started first with her small, scrawny frame, her pink pajamas stretching around it as it begun to fill out, pulling tightly at the cloth, and causing the sleeves and pant legs to retract up her once bony arms and legs. Next came two little bulges pushing out on her extremely flat chest (Julie being a late bloomer in the puberty stakes), quickly growing bigger and biggerr until you could clearly see two quite large and substantial breasts almost bursting their way through the material of her now over stretched top, displaying a lean and rather toned stomach beneath. Even though this was your sister and you knew it was wrong, the sight of those two prominent mounds now fighting for freedom within the ridiculously small pajama top did cause somewhat of a reaction in your pants, the sheer spectacle of seeing a pair of tits inflate right before your eyes being absolutely mesmerizing. Taking your eyes off of your sister's rack for a moment, you then watched as further below, her hips also began to stretch and widen, pulling further at her pajama bottoms and giving her what you could only describe as a perfect hourglass shape.
"Holy shit!" you thought to yourself, utterly amazed by this transformation, never imagining that skinny little Julie would ever possess a body quite like this, looking far curvier and better proportioned than either Alice or your mom, almost as if she had the body of a model from a Playboy magazine or something. Her face had also changed quite dramatically, being of course instantly recognizable, but at the same time much more mature looking and more refined. Gone was the cute little, innocent girlish visage with her button nose and freckles, replaced instead by that of a very attractive and sophisticated young woman, possibly in her mid to late 20's.
"TA DA!" Julie giggled with pride, jumping up off the bed and spinning around to show off her new figure, before quickly examining every minute little change, shrieking and squealing with delight. You meanwhile, just stood there watching her, utterly captivated as your once tiny, 13 year old sister, danced around in her ridiculously overstretched clothing, gushing over her now much taller, curvier form, before he attention once again moved back towards you. "This is so cooool!" she beamed, grinning like a madman as she placed a hand on her head, trying to estimate her new height, "I've got to be like a foot taller or something...almost as big as you!" This was certainly true, Julie having always been at least a foot shorter than you were (if not more) in the past and now appearing almost the same height.
"And check out my boobs!" she then said, her attention turning to the large breasts desperately trying to escape her top, as she squeezed and fondled each mound, "I've finally got boobs! Big boobs! Way bigger than mom's, or even Mrs. Cunningham, the Gym teacher!" They certainly were big you thought to yourself as your eyes were drawn to each spherical mound pushing it's way out of her pajama top as Julie continued to cup and fondle her rack, feeling a few further twitches of arousal coming from your underpants, ashamed to admit that you were actually becoming excited looking at your little sister, but being unable to help yourself, her clothes being oh so tight and her breasts oh so large (never mind the fact that they were bouncing wildly around in front of you). Unaware of the effect the enthusiastic exploration of her hefty chest was having on you, Julie continued to grope away, babbling excitedly as she did about how much she'd always wanted big boobs and how jealous various classmates were going to be when they saw just how busty she was. "Janis Henderson always used to make fun of me for having no boobs," she told you with an extremely smug little grin, "Just wait till she gets a load of these! She won't be so proud of her precious training bra when she sees me now!"
"No...no, she won't..." you replied, barely listening, your focus being firmly on both the spectacular display of cleavage visible through her overstretched neck hole, as well as two large and very obvious indentations of her nipples.
"I wonder how big they are...?" she then asked herself, before removing her gaze from her chest and noticing your captivated stare. "Well, well, well...Looks like I'm not the only one who likes these things." Catching your attention, you quickly yanked your gaze from her chest, feeling slightly flushed and ashamed at having been ogling your own sister like that as you saw a mischievous little twinkle appear in her now almost sultry blue eyes. "Do you like my big boobies, Matt?" she smiled, hefting each one up as she said it, causing you to let out a nervous little gulp.
"Uh, wuh-what...?" you muttered, not entirely sure what to say, it being obvious you were staring, but not really wanting to seem like some sort of weird pervert.
Julie however, continued on anyway without a proper answer, her eyes fluttering briefly over the bulge that had been slowly growing within your pants. "Hee hee. That's alright, I can see you do," she giggled, pointing to your semi, "I can see you've got a...a...y'know, a thingy in your pants." You of course tried to deny this, shifting your legs a little to try and hide your bulge. Not that it was of any use, Julie being able to see right through your lie, confessing to you that "It's alright if you do, I don't mind. I know you like girls with big boobs, I've seen some of the things you look up on your computer."