It didn't take long for 90% of the town's females to become infected. It took weeks for authorities to track down the source of the "horsecock epidemic". They found Kyle, who was rather proud of himself for causing this much pandemonium. Jen was unable to use the curse rationally, due to the almost constant state of lust she was in. All she had been able to do was make it so that women wouldn't be transformed should they come into contact with the cum.
But the dare she'd given had damned the town. She dared everyone to remain horse sluts for the rest of their lives. So the town was forced to accept the reality of their situation. Over half their population were now horny equine whores. School was never the same. The girls who had been transformed weren't allowed back, as all they did was fuck and masturbate.
Jen and her sister went to a special farm, where their cum was harvested and used to get mares pregnant. The first time Jen climbed on a real mare had been incredible. It wasn't as good as fucking her mother or sister, but it was close. But being fucked by a real stallion, that was better. A true beast taking her from behind, Jen lost herself in the bliss.
Six months after her transformation, Jen was content to stay at home all day. Jacking off her morning wood, and them having breakfast with a side of warm cum courtesy of her mother. Life was good.