Development App (Commission, Centaur, Growth, Hyper, Multi)

Story by Tosaku No Kishi

This was a fun commission from Shironomi on my discord.

A young centaur futa didn't grow as she'd hoped, but her friend gets a mysterious app that can change all that.

Holly wasn’t like most centaurs. Most in her age group stood head and shoulders above her, almost torsos above human girls, with some that nearly doubled others. Her mother was one such centaur, several feet of legs that supported a voluptuous torso with tits half the size of Holly’s whole body. All that said, she didn’t show much of any jealousy about it.

The fact she wasn’t too big for most humans played a part. Centaurs had a problem after puberty wreaked its havoc, that being sex with humans was nigh-impossible with three and a half foot dicks, as was the average. For that reason, possibly the only one, Holly was popular with her classmates. She couldn’t offer rides like her kin, but she could ride others. ‘Could’ being the core word. The centaur was too shy about sex with anyone but her closest friend, Jane.

She could’ve grown into something truly spectacular, though. The potential was there, that’s what saddened Jane the most. Having met Holly’s parents, both equally massive even by centaur standards, it was a wonder how their child turned out the way she did, though her shyness made sense. Her parents were almost obnoxious in how ‘out’ they were about sex, which had led to may awkward encounters. Both for Jane and Holly.

That was when Jane made a discovery that changed her whole life’s focus. Go figure, it was an app, not a game or some weird health care thing, though perhaps it was more of a mash-up of the two. The first page was just a typical home screen, a few bars of ‘progress’ and daily objectives. The real kicker was the focus; sex. The bars were dicks, the weird stamina gauge was a pair of testes, and she was pretty sure all the buttons were just nipples or clits. On another screen was a body.

At first, it resembled hers eerily well. Like something had taken 3d scans of her from every angle, though she hadn’t a clue how that was possible without her knowledge, but there were settings. One changed it into the shape of her dearest friend; Holly. She left it alone for a few days, until after she and Holly slept together again.

It was an ongoing arrangement between them. Both had needs, Jane was flexible enough to handle a two-foot horse cock, and Holly was a futa centaur, of which Jane had yet to meet one without an insane libido. They’d been friends since junior high, which turned intimate after a chance encounter in the restrooms. Neither wanted a relationship, so it was a friends with benefit scenario, which suited both just fine. No strings. No commitments. Just good fun.

Which only got better as Jane dove into the app. The ‘quests’ were for all manner of sexual acts, from some simple like oral, to being edged ten times in a row, and even living a full day in bondage or with a full blown erection. Which Jane made every effort to engage in. Most were easy, they already did them on a regular basis, but it took some convincing for Holly to go a full day with vibrators inside her. After that, however, it wasn’t so hard.

The app claimed responsibility for that. A menu came out that showed Holly’s stats, from her sizes all the way to her psyche, represented as a meter going from ‘lewd’ to ‘reasonable’. It started deep into ‘reasonable’, but each successive act tilted her more in the opposite end. Subtle things changed about her wardrobe, such as her shirts dipping lower, or the slight swing to her gait now, like she was trying to show off for the masses. And she had more every day.

Completing those quests earned points, which Jane kept stored, but it gave automatic bonuses anyway. She’d first discovered it a year ago, saving points for when the urge really struck, and basked in the way Holly developed. The centaur once stood just a few inches over Jane, now she towered as she was meant to, with over a foot added, though her assets stole the show and encore. It did result in some challenges.

Sex wasn’t an option for starters. Flexible as she was, Jane couldn’t handle her friend’s new size. From two feet, all the way to four and a half fucking feet of pure womb wrecking cock, and her breasts had exploded just as impressively. Not to mention her ass. Odd as it was to see a horse body with human curves, it was undeniably sexy to watch her cheeks jiggle and sway with the clopping of her hooves.

“Are you sure about this?” Holly asked. Jane had spent the night, using an impressive arsenal of skill and toys to get her friend off over and over, until the centaur’s cock looked ready to explode. Now, they were ready for school, with one minor addition. The ‘erection’ quest offered the biggest rewards and was simple to accomplish, b

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