Yes, and it's unexpected

After 30 minutes or so, you are already getting bored of the class. You quickly realize that everything that the prof is saying has already been covered in high school, although there seems to be quite a few students who haven't done it by the amount of questions she is being asked.

"Sorry professor, I still don't get where the 64 comes from", a girl at the front asks Ms. Hartley.

"Well, you have to multiply the exponent of x with the number in front, so that makes 4 times 16 which is equal to 64", she replies for the 5th time, still trying her best to explain how simple differentiation works.

"Damn, she has a lot of patience", you think to yourself as you observe your prof more carefully. She has shoulder-length, wavy brown hairs with a well-defined nose. Even though she looks young, she isn't afraid to engage with the students and seems passionate in her teaching.

Suddenly you feel a hand on your right thigh. You look down just in time to see Steffi's hand edge closer to your crotch.

Surprised, you turn your head to the right to see her face, but she is looking straight ahead, still focused on the professor's explanations as if nothing is happening.

"W-what are you doing?", you ask her quietly as you feel her hand start to caress your quickly hardening dick through the front of your jeans. You also have a quick look around to make sure nobody is watching.

Steffi doesn't seem to have heard your question, or maybe she just ignored it. Your fully-hard member is now straining against your pants, and you feel it increasingly hard to focus on anything else.