#sadomasochistic

"I… I don’t know," you manage to get out. Your voice is a pathetic little squeak.

"I don’t know." He repeats it, mocking you. "Of course you don’t know. You can barely stay focused."

His shadow falls over you as he leans forward. He’s so close. His scent makes your head swim.

"Look at me."

You lift your head slowly. His eyes are dark, narrowed with frustration. You think he might just grab you and shake you.

"Are you even trying? Or are you just wasting my time?"

"I’m trying," you whisper, and it’s true. You are. You’re trying not to squirm in your seat. You’re trying not to let him see how his disappointment makes you drip.

He runs a hand through his hair. "I’m starting to think this is pointless. You’re just not getting it."

The words land like little stones, and with each one, you leak a little more. It’s too much. If this goes on any longer it’s going to be impossible to hide the wet patch forming on the plastic of the library chair. You have to get out of here. You have to fix yourself.

"I need to… I need the bathroom." You push your chair back, the legs scraping loudly on the floor.

He waves a dismissive hand, already looking back at the textbook as if you’re not even there anymore. The humiliation of it is a fresh thrill. You practically run from the room.

In the bathroom, you splash water on your burning face. You lean against the sink, breathing hard. You’re a mess. Hopeless. You press a wad of toilet paper between your legs, trying to soak up the evidence of just how pathetic you are for him. After a few minutes, feeling a little less likely to fall apart, you head back.

When you walk in, he’s not looking at the book anymore. He’s staring at your empty chair.

"What the fuck is that?"

You follow his gaze. On the smooth, beige plastic of the seat is a dark, damp patch. A perfect little outline of where you were sitting. Your heart stops. Your blood runs cold, then hot.

He looks from the chair, to your face, then back to the chair.

"Did you get so scared of a little math problem that you wet yourself?"

Your mouth opens, but nothing comes out. This is so much worse than him thinking you’re stupid.

He stands up, walks around the table, and stops in front of the chair. He crouches down, inspecting the wet spot like a detective at a crime scene.

"No," He looks up at you, "you like being humiliated. I bully you a little, and you get this wet."

You can only stand there, exposed, barely able to breathe.

"Well, the least you can do is clean up your own mess."

You stare at him, confused. "I… I can get a paper towel…"

"No" He shakes his head. "You clearly need some discipline. Lap it up with your tongue, slut."

The words don’t compute at first. He can’t be serious.

"Lick it clean."

His hand shoots out and grabs the back of your neck, his fingers digging in. He forces you down to your knees in front of the chair.

"Don’t waste my time."

Your face is inches from the plastic seat. You can see the damp sheen of your own arousal. The scent is faint, but it’s there. Humiliating. You hesitate for a second too long, and his grip tightens, pushing your head forward until your nose bumps against the chair.

There’s no use fighting it. You give in.

You stick out your tongue and give a tentative lick. He grunts, the first sound of approval you’ve heard today. You close your eyes and start licking in earnest, trying to erase the spot, your tongue swiping back and forth, back and forth.

His hand slides down your back. It rests on your ass for a moment, then hooks into the waistband of your shorts. With a single, sharp tug, he yanks them down to your knees, taking your wet panties with it.

Before you can even react, two fingers shove right inside you.

You gasp, your mouth falling open against the chair. You’re so, so wet. He doesn’t need any prep. You’re a fucking fountain for him. His fingers are brutal, plunging in and out, ramming against you.

"You’re so fucking pathetic," his voice is rough, right against your ear "Leaking all over the goddamn library furniture like a stupid bitch in heat."

Every thrust of his fingers is a spark. Your hips start to buck against his hand, a mindless, needy motion. You’re on your knees, your face pressed to the chair, lapping up your own mess while he paws at your cunt. It’s the most disgusting thing that has ever happened to you.

And you’re about to cum.

"Sir I'm—I’m…" you whimper, barely even processing what’s happening.

"Get it over with." He drives his fingers in deeper, harder.

You can’t form words. Your brain just… shorts out. The pleasure is too sharp, too laced with humiliation. It builds and builds until your whole body locks up. You collapse against the chair, twitching, your inner muscles clenching violently around his fingers. He holds you there until the last aftershock fades, and then pulls his fingers out with a wet schlick.

"Get up."

You stumble to your feet, not even having the sense to pull up your shorts. You see him, already back at his side of the table, unzipping his jeans. He pulls out his cock. It’s thick and hard, jutting out from his pants. It’s everything you’ve been imagining and more.

"Sit down," he says, pointing not at your chair, but at his lap. "We’re not done until you understand the problem."

Your legs move on their own. You go to him, turn around, and slowly, carefully, lower yourself onto his cock. You gasp as he slides inside you. It’s a tight fit, stretching you, filling you up. He reaches around you, his arms caging you in, and grabs the textbook.

He holds it in front of your face. "Now. The derivative of x-squared plus one, all to the power of three. Fucking do it."

You stare at the symbols again. They’re still just squiggles. You can’t think. You can only feel him, thick and hot inside your ruined pussy.

"I… uh… three times…" you start, your voice trembling.

"Three times what? Use your words."

"Three times… x… squared…?"

"Wrong."

He slams his hips up, driving his cock deep into you. "No, you stupid slut!" he snarls, and the force of the thrust makes you cry out. "Derivative of the outside first! Three times the whole goddamn function to the power of two! How many times do I have to say it?"

You sob, a tear rolling down your cheek. "I’m sorry…"

"Don’t be sorry. Be right." He grabs your chin, forcing you to look at the page. "Now the derivative of the inside. What’s the derivative of x-squared plus one?"

You’re shaking. Every time you breathe, you can feel the head of his cock rubbing against your cervix. "Two… two-x?"

"Finally." He rewards you with a slow, grinding rotation of his hips. A moan escapes your lips. "See? You’re not completely useless."

He walks you through the rest of the problem like that. Every correct step earns you a slow, teasing grind. Every mistake, every hesitation, earns you a brutal slam of his hips and another venomous insult. He calls you dumb, a whore, a worthless cunt who’s only good for one thing. And with every insult, every punishing thrust, you get closer and closer — to the right answer — and also to cumming again. It’s a cruel form of reinforcement learning spurred on by his cock and the hateful words in your ear. "Now write the final answer," he commands.

You can’t. Your hands are gripping his arms like a vice, the pressure building and building to an unbearable peak. You’re about to cum again, just from the friction and the filth. You shake your head.

His grip tightens on your waist. "Write it."

Somehow, you obey. Your hand is trembling so badly you can barely hold the pencil. You reach over, your whole body stretched taut over his cock, and scrawl the final, correct equation on the page.

He looks down at your shaky handwriting. At the right answer.

"Good girl."

He slams his hips up into you one final time. That’s all it takes.

Your whole body rattles. You come apart, an endless orgasm that leaves you completely undone, twitching and whimpering against him. He lets you ride out the aftershocks, then he floods you, his hot cum shooting ropes deep inside.

He pulls out. Abruptly. You feel suddenly empty, hollowed out. A thick, creamy white trail drips from between your legs, running in a messy line down your inner thigh.

He pushes you off his lap and you stumble, barely catching yourself on the edge of the table. Then he glances down at the textbook, at the perfectly correct answer you wrote in your final, desperate moment.

"Looks like you’re finally getting it."

He stares back at you, a mess of sweat and cum and tears.