Giving her one last smile, the teacher returned to his desk, and the three girls waiting there. Making them face away from the class and bend over his desk, the short skirts already allowed their asses to reveal slightly. But if they thought that was bad, they would soon feel their skirts lowered to their ankles. If they tried to move, a sticking charm would find their upper bodies glued to the desk. Now, the three girls' asses were on display, with Hermione's white ass in the middle of the two brown butts.
Suddenly, a slap hit Parvati's ass cheek. It was not hard, more like a playful spank. But after a few seconds, another hit, and another, and so on. Each slap was slightly harder than the last, and while even the harder ones were soft, the consistency caused even the soft hits to eventually sting.
This targeted approach was soon repeated on the other ass cheek, and then the four other ass cheeks waiting. Of course, Hermione's white skin allowed a red mark to show itself on the skin, whereas the Patils could hide the marks a little better. "Okay." He said, waving his wand, and the twins found themselves unstuck. "You may return to your desks. This punishment will be repeated but worse if you fail to fix yourselves before next lesson." He told them, and they'd find their skirts missing. So the two would return to their desk without anything covering their lower bodies.
Hermione was still stuck though, as the teacher was not done with her yet. "I warned you, don't question my methods." He reminded her quietly. "Now, Hermione has volunteered herself to be the display for our next lesson. Today, we are going to learn about the lower body sexual anatomy of a female. The parts you will all be focusing on, is the butt cheeks, the ass hole, and the vagina." The Professor explained.
"The butt cheeks are pretty obvious, as everyone has them." A hand moved to Hermione's butt, gripping it and giving it a small squeeze. "Some females enjoy ass play, whether it is giving it a squeeze, a slap, a kiss, or something else." With his second hand, Curtis opened up Hermione's ass cheeks. "Now, this here is the ass hole." Gently, the teacher's finger slowly rubbed the hole. "Again, pretty obvious, since everyone has one. With both men and women, some people like this being played with, others don't." Curtis explained, his finger tip slipping inside for a brief second, before pulling out.
"And finally, the vagina. This is where the magic happens. Where sex will occur more often than not." As he spoke, Curtis reached for a black dildo identical to the one he let Ginny borrow. "Of course, for first timers, a hymen does affect the passage." He explained, slipping the dildo inside. Using the numbing agent, Curtis pushed the dildo inside of Hermione until the hymen broke. Pulling it out, it was soon replaced with a larger one. "Okay, so, we will see what sex is like, simulated with a dildo. Girls, if you would like to get in a line, you can give it a few thrusts and try it out. Be gentle though." He warned, placing the dildo inside the nerdy girl and watching her reactions.