Was quite hard to begin with given that, through some strange fluke of realities, denizens of her world were vastly larger than the chief inhabitants of this planet… 'Oorth'. Also made even harder by the fact that, duel to conflicting natures between a dimension seeping with magic and one completely lacking it, Equestrians find themselves experiencing strange… changes to their bodies.
She had heard what had happened to Applejack, and even though she's back home on the farm… her immense milk-filled udders have yet to dissipate.
But the yellow creme-colored pegasus had been extremely curious about these little 'Hoo-muns', and from what Twilight had shown her, they did indeed look to be quite cute. So she had asked to go visit, to meet these cute creatures… and now Fluttershy wished she had simply stayed home.
Twilight had indeed warned her about the strange effect this dimension had… but she had just not quite elaborated too much upon it. Granted, it seems to (apparently) effect everypony differently.
The gentle shy pegasus found herself overcome with strange new feelings, a warmth mixed with a craving.. an urge. Fluttershy had always found a way to handle, or mitigate, her 'heat'. Thanks in no small part to the efforts of Zecora. But this was like 'estrus' cranked up to 10… or 11 even! One top of that… her posterior… her plot… had expanded… BALLOONED to a massive size. This only added to her uneasiness, and her growing embarrassment as she tried to 'hide' amongst the buildings…. hoping this would pass.
It never did. On the plus side, she got to meet quite a few of the hoo-muns, and found them to be every bit as cute as she had hoped.
And a bit… alluring… sexy even… despite their stature. But the pegasus sincerely hoped that THAT part was just her 'heat' affecting her mind. ——
Another entry into this pseudo-series, involving giant ponies visiting our world… and being effected by the clash of dimensional natures.