[NOTE] Please do not downvote the fanfic solely based on the fat fetish. If this is not your interest, do not read!
Rainbow Dash has become enticed by Pinkie Pie's recent behaviour - backing into her basement for hours, emerging with an even flabbier stomach every time. She finds herself staring in awe, intrigued by her new attraction to Pinkie.
Out of uncontrolled temptation, Dash creeps down to Sugarcube Corner at night, before being greeted by the beautiful bulging pink pony. Pinkie drags her, strapping her into her gluttonous fate.
Ultimately, from cupcakes to gateaux, cheesecakes to cheese pastries, Dash is forced to overindulge until the dessert store is deserted. Pinkie then washes it all down with a calorific milkshake, washing Dash's flying career away in the process. But Dash, finding her new enjoyment in the fetish, submits with satisfaction to Pinkie's plans...