i distinctly remember two expansion based stories i remember reading on Lit-erotica around 2014-2017what i can remember from each are mentioned below
story 1): a woman buys some lotion/powder at a store that causes her breasts (and possibly ass) to grow while she massages it into her skin, i remember there being a bedroom scene and that the lotion /powder had something to do with chili, i wanna say even the story was called "chili powder"
story 2): this one had something to do with a witch that granted the power of growth to a random girl, making her into her prodigy, and the girl used the powers to make her rivals breasts and ass grow huge while the rival didnt notice right away while she was reading a magazine, then there was one or two more "victims" before the story ended