Celestia thought she would have exploded by now. Millenia has passed since she was cast out of Equestria by her former fellow princesses for a crime that... she can't even remember. She can't recall their faces or why she was exiled. All she can remember is that they unlocked her "true potential" and threw out. She was once the diarch of the sun, and now she was a living solar panel. All the energy from the Sun being stored infinitely within her breasts and butt. She was doomed to swell and grow geometrically until one day her body can't handle it and she bursts.
Or so she was told. Despite the increasing pressure within, and her gradual immobility, Celestia has managed to survive. Each year, her gait slows, her time spent upright lessens, the orgasms racking her body increase in ferocity and frequency. Yet she survives. For how much longer, she doesn't know. Or care. She has long since forgotten the prim and proper, stern and thoughtful ruler. She lives only for her curves now, wandering a destroyed civilization that may be Equestria, feeling the light feed her insatiable sexual appetite.
Heaven or hell? Both in one. Celestia cries out as a particularly strong gust of wind hits her bust. The resulting orgasm-- the strongest one this week-- drives her mind into the familiar blackness of catatonic pleasure. And it brings her down to her knees, in ectasy, for the tenth time that day, the hundred time that week, the millionth time in millenia...

I was playing with novel.ai and a drabble came to mind.