You

You contemplate the choice for a moment.

Julie is a clean slate for your transformation; you could think of any number of interesting things that your power might do to her, from making her even taller, to filling out that ass of hers, to something less immediately visible like making her even more of a blowjob queen (how, you're not sure, but then again you did manage to give that cop a magical instant pregnancy, so the limits of practical reality clearly isn't a concern for you anymore).

But watching Julie so easily handle you lit something of a fire inside you. You'd been getting used to this new body of yours, taking some pride in being bigger and stronger than everyone you meet -- not just that, but just being too much for everyone. (Well, everyone except those chosen women in your growing collection of partners.) Julie so easily sucking down your cock to the hilt was hot, but also... a little annoying?

In the end, you figured the power hadn't done wrong by you yet, so there wasn't all that much risk in choosing you.

Color splashes back into the world, and you feel the first of your huge loads rocketing forward out of your cock and down into Julie's waiting throat. Your dick spasms and lurches as you come, and you arch your back, the pleasure filling you from head to toe...

...and then you feel the stretching sensation, and realize: you're getting bigger.

In every direction, all at once, with every jet of cum from your cock, you're growing. Taller, wider, more muscular. Inch after inch piles onto your already towering frame, until you're over easily over seven feet and wide as a refrigerator.

And your cock! You look down to see Julie's lips stretched taut around your girth, four inches from your pelvis, her eyes watering slightly as your enormous load continues to pour down her gullet. Each single blast of cum feels bigger than anything you ever produced before your changes, and there's just so many of them now.

She appears to be struggling slightly, and so you reach down and, very gently, pull her off your cock, which lets loose one final rope of cum right across her chest. She shudders and takes a deep breath. "That was... wow..." she says, eyes watering, a little drool leaking out of the edges of her mouth. "I've never seen a cock as big as yours, ever."

"No shame in not being able to take all of it," you rumble. Your voice feels even lower than before, all bass and gravel. "It's over a foot long, after all."

"Closer to sixteen inches, I think," Ava chimes in from behind you. Wow, she feels tiny now; her tits are pressed against your lower back! If you get much taller, she'll just be at blowjob height with the two of you standing next to each other!

A stray droplet of cum wells up at the tip of your cock at the thought of that, and Julie eagerly licks it off, smiling as she does so. "And so much cum! I feel like I just ate another helping of dinner with how much you just came down my throat." She rubs her stomach, which lets out a gentle gurgle. There's no visible change -- you didn't come that much, don't kid yourself -- but even the idea of your cum being enough to cover someone's meal is another little ego boost.

"Well, thanks for showing us that thing in your room," Ava says, giving your cock a little pat and helping you pull up your pants. "It's getting late, and I'm sure David's mom is wondering where he is."

"Ooh, all this and he loves his momma, too?" Julie says, winking at you as she stands and starts cleaning your cum off her chest. "You've got yourself a real keeper here, Ava."

"Don't I know it!"