Twilight's assignment was to work on developing some new spells, and Celestia is visiting Ponyville to check up on her progress. Unfortunately, a series of distractions means that she has precisely one spell developed enough for analysis: a dick-growing spell. Naturally, she's rather reluctant to show that to her teacher, but if the alternative is getting a bad grade, it may be her only hope.

Takes place in the same continuity as the three linked fics, but those fics aren't required to read this one. Futa content, obviously.

And yes, I know the cover image is awkwardly cropped. I needed a picture of a stern-looking teacher Celestia, and this was the only one I could find. And I had to crop it because the full picture, while great, doesn't really match with the content of the story.