Instinct

This is an excellently told adult story.

Cologne has managed to do something to Ranma, making him remain in his girl form. She is suffering basically from a forced increase in her sex drive, a sex drive directed towards being pleasured by a male.

The male Cologne would prefer turns out to be Shampoo, who has taken on male form, but the male Ranma-chan ends up giving herself to is Ryoga.

The story does very well describing the psychological self-examination that Ranma-chan goes through; fighting as hard as she can against her own human instincts towards sexual activity. Still, in the end, she must give in to those instincts, a surrender that will change her life forever.

This is a relatively short story, but packs a lot of punch in its few pages.