Take Anatomy 101

Kasha said, "Yes, this is the class I will take," and took a seat at a desk that was a safe distance from the other three students.

The professor stepped up to the anatomical doll, grabbing its cock. "This, as you should know, is the male organ: the penis. Down here below it are the balls. For most mortals, they are born with either a penis or a vagina. But we succubi are different. All it takes is a simple ritual and you can give yourself whatever genitals you want. An important part of your education is to understand which ones are best suited for different circumstances, and how to best use them. It's important to understand how best to make use of a cock when you have one, and also how best to pleasure someone else's. Thus, today's exercise will be in learning how best to use a cock."

With a snap of the professor's fingers, a magical circle appeared beneath each of the four students, Kasha included. She felt her loins burn, then she felt something stretching. Pulling her leather armor away, she could see that... she now had a penis. Glancing at the bulges clearly visible beneath the succubi skirts, it was clear they each had one as well.

"Your assignment is simple: the first of you to ejaculate with your new cock fails. The rest pass."

All three of the succubi schoolgirls turned to Kasha with hungry eyes.