Found by Sheila (beach edition, outline) Giantess/Shrinking & Farts chapter 14 by Sex-Caliber

She took a few moments to savor your body a bit longer, before letting you out so she could move around undistracted—and brought you up to her face so she could take a better look at you.

You, of course, were stunned by the brand new view of her whole, colossal body from such a "unique" perspective—and turned beet red as you processed that, despite the danger you were in just moments ago, you had in fact literally just been inside her.

Surprised to recognise your shrunken form, she was filled with a number of questions: aside from the obvious "how on Earth did you shrink like that?", she was also wondering what possessed you to try and jump into her big, bassy booty just now.

It occurred to her after a moment that so much time around super-attractive and super-gassy women like herself, her daughters, your mother and their mutual friend group might have instilled a certain taste in you—but upon her asking you (somewhat flirtatiously at that), you insistently denied it, trying to explain what really happened.

While she was somewhat doubtful you were telling her the whole truth, what just happened between the two of you gave her an idea: she knew Lillian had a major crush on you, and was already fully supportive of her as a mother, but maybe she couod also do more to "help things along" in her own way…