She doesn’t even notice

Luna wakes up an hour or two later, still caked in dry sweat and cum, but fully furless and with all of her human parts back in place. She rolls over and stretches, yawning after her thrilling sexual experience, and sits upright. She still feels bloated with cum, even though she’s returned to her original size. She embraces herself, loving the feeling of warmth planted deep within her.

With a bit of reluctance, Luna cleans up and dresses herself, before heading off to bed. She doesn’t realize it, but her sexual adventure has consequences beyond that day’s fun.

Over the next few weeks, something feels off in the back of Luna’s mind. She tries to keep it from interfering with her classes, but she finds herself falling asleep in class more often, and craving unusual foods, some of which aren’t even served by the Hogwarts House Elves. Her symptoms grow gradually worse - and her belly slightly expands - until about a month after her adventurous fuck.