You have her try and let out a fart Your Own Shrinkray Adventure chapter 8 by Marak077

You can feel Maria stunned at your request, as her butt jiggles from her jolting. "¿En serio?"  

You confirmed your request. It took a moment for her to compose herself. Rubbing her butt together along with you between them. It's no surprise she's a little worried what'll happened if you get farted, nothing good she thought. And you too, would also think that, but morbid curiosity has a way with ignoring logic.

Then, her answer to your request are-