You're late for math

Despite eating en route, you arrive to your afternoon math class to find it already in full swing, with the students in their seats and the elderly Russian teacher, Mr. Ivanov lecturing in his heavily accented voice.

As you barge into the room in something of a hurry, Mr. Ivanov turns to look at you impassively, sarcasm clear in his voice as he addresses you, "ah, Miss Isabella. How nice of you to join us. Since you did not find it necessary to arrive on time, I assume you have already covered today's material on your own? Please, answer question on the board."
He waves you forwards and hands you a piece of chalk. One glance tells you that it's something you haven't learned yet...you stand dumbly in front of the board trying to figure out some way to bluff your way through it, but eventually have to step back helplessly.

Seeing you unable to answer the question, Mr. Ivanov pulls his chair out from behind his desk and takes a seat in front of the class.

"As I thought...now come here for discipline. It is lucky you are attendant, or I could not do this."

Once you step into his arms reach, Mr. Ivanov pulls you across his lap and hoists your skirt up.

The lack of underwear seems to startle him for a moment, until he comments dryly.

"No undergarments...I think I can guess what you have been up to instead of going to class."

You flush red as the class bursts out laughing at that, then yelp as he begins spanking your exposed ass. It hurts, but mostly it's humiliating...the entire room is seeing you get your ass slapped red by an elderly Russian man.

By the time he's done, you can feel a hard bulge pressing into you from below...luckily Mr. Ivanov can't exactly delay class anymore by taking the time to 'use' you.

He lets you lower your skirt and return to your seat, though you notice a lot of students eyeing you hungrily after the show you just put on for them...it's hard to concentrate when there are at least four visible bulges in the seats surrounding yours. Your backside hurting doesn't help either.

Class passes slowly, and it's a relief when it's finally done.