Nightmare Moon felt a pressure build up in her belly. Celestia smiled as she motioned her head towards Nightmare’s middle. The dark Alicorn’s eyes shot wide open as her belly expanded rapidly, even more so than her sister’s. Her small navel peered through the light purple clothing as her belly bloated. In the middle of a storm of gurgles emitting from her stomach, she felt something inside her, something that wasn’t her growing intestines. Nightmare Moon’s jaw dropped as she felt a kick from inside her round expanding girth.

"You made me pregnant?!" Nightmare Moon clenched her teeth as the pressure in her belly continued to build up. All Celestia did was smile as her sister’s plight.

"ooooooo-aaaaaAAAAH-!!!" Nightmare Moon felt like a balloon, swelled up, filled, round, and about to burst.

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Oh, Nightmare Moon, your roundness intrigues me ever so…

Sequence created by an idea from  somedude184

Hope you guy’s like what I have in store~