Shameless You & Pinkie sexy times.
Pinkie's been baking up some 'special' treats and you're the test subject for her fetishy fantasies.
Chapter One is tame, things start going off the rails thereafter when Pinkie's baked goods start doing inflation/deflation things to you.

[Author's note: This is one of my early works, and was my first time writing lewd. I don't feel like it reflects my modern writing, but I believe in leaving the old stuff up - so enjoy with a pinch of salt ;) ]