You're presenting something in math with Roman. As you're talking about it, you compute and discuss it, Roman is just standing beside you, his hands moving closer to your ass while you're writing on the white board as a joke, until he accidentally does it and his rough palm directly smacks your ass hard enough to make a loud sound. Everyone in the room looks in front, staring at Roman. Roman doesn't do anything about it and just keeps grabbing your butt.

After your presentation, you sit down on your seat but you feel your butt hurt when you sit, you look over at Roman and see that he's grinning at you.