"Well, if gifts aren't allowed, is there any other way I can thank you, sir?" she asked, softly. She was dressed in an even more risqué manner than usual, in a white boob tube and a very short denim skirt. Her knees parted, raising the skirt and showing me more of her smooth thighs.

I gulped at her blatant innuendo. "No, Julie, I can’t…"

"Don't you find me attractive, sir?" she pouted, tossing her blonde hair. "I’ve noticed you looking at me. A lot." She stretched her shoulders back, pulling the thin fabric of her top tightly over her braless nipples. "And you did touch my leg last week."

Shit. I thought I had been fairly discreet with my glances at her tits and legs during our weekly tutorial meetings, but evidently not. And I wasn’t going to be able to claim that the leg-touching incident was accidental.

"You're a very beautiful girl," I said. "But any relationship with a student is a serious disciplinary issue. I'd lose my job. It's an abuse of my position of authority. And there’s the issue of conflict of interest." 

She looked at the piece of paper I had just given her, the cause of her current feelings of gratitude. "But now you've given me my degree result, surely there’s no conflict of interest, is there, sir?" 

She had a point. But I’d still be in deep trouble if anything happened and word got out.

"I'm so grateful to you, sir. I could never have got a first without all your help!" 

"Oh, I'm just doing my job. You're a very talented and hardworking girl and you really deserved your result." 

"Don’t you want me, sir?" She scooted lower in her chair, making her skirt ride even higher up her legs. I couldn't take my eyes off the soft skin of her thigh. "I think you do."

"Of course I want you, you’re a gorgeous, sexy girl, Julie, but we can't, someone might come in. I’d be fired. I've got another student coming in fifteen minutes anyway."

"Yes, I know, my friend Sarah. So you could be in big trouble for stroking my leg last week? You’d better hope I don’t tell anyone, sir."

This was getting surreal. Was I being blackmailed into sex by a girl half my age? My mind was racing, heart pumping, cock thickening. "Look, maybe, tonight or tomorrow, we could meet up somewhere?"

She shook her head. "My parents are picking me up this evening and taking me back home to Edinburgh. It’s now or never, sir." Her eyes dropped to the growing bulge in my trousers. "You want it too, sir, don’t you? Let’s do it. Here, right now in your office. That would be so hot. I’ve got such a crush on you, sir, and I’ve always wanted to do it with an older man." She licked her lips and stood up.

I grabbed her slender waist and pulled her towards me. The boob tube came down easily with a firm tug. Her full breasts burst out in front of me and I buried my face between them, feeling her soft skin against my stubbly chin.

"We’ll have to be quick, Julie!" I glanced over her shoulder at the clock. We had twelve minutes.

I pushed a hand between her legs, aiming to rip her knickers off. But under her skirt, my hand met her smooth, moist folds, squirming eagerly against my groping fingers.

Her fingers opened my zip and plunged in, quickly unleashing my cock, pulling it up and giving it a few quick squeezes.

My lips locked onto a stiffening nipple and I parted her labia with my fingers, feeling her silky, slippery slit. She rocked to and fro, working herself off against me, panting.

I pushed her backwards against my desk. She hopped up onto it, scattering my papers and books. Her legs coiled around me and her skirt bunched up around her waist. Eight minutes.

She guided the head of my cock to her pussy. There was a brief moment of exquisite resistance as the thick head of my cock pressed against her tightly clenched muscle. Then I felt her relax and yield. She gasped. I tried to stifle my moans as I penetrated her. Her lubricated lips peeled back my skin and enveloped my bulging cock.

I rocked my hips forward, pushing my cock deep into her, while she pushed back, impaling herself fully on my shaft. I groaned again. Six minutes.

I put my hands on her breasts and steered her down onto her back on the desk, lifting her legs higher so I could fuck her deeper.

I slipped two fingers down between us, stroking beside her clit as I rammed her hard, pushing her further up the desk. 

She started to moan. "Hush!" I whispered. Her head fell back, her eyes closed and her mouth opened wide as she took in a deep breath and held it for a moment. I felt her start to shudder, her muscles clenching and her pussy tightening around me. I clamped my hand over her mouth as she started to scream, trying to suppress the noise.

Feeling her cum on my cock tipped me over the edge. I felt the unstoppable rush, the uncontrollable urge to sink deep into her and hold it there, pumping my ecstatic relief into her.

There was a knock at the door, just as my contractions were fading. 

"Just a minute!" I called out.

I pulled out of Julie, tucked my cock away and zipped up. She got off the desk and pulled her skirt down over her cum-filled pussy.  She went to the door and opened it for the girl waiting outside.

"Hey, Sarah, you owe me twenty quid!"

As she stood there, a trickle of creamy fluid ran down her thigh.

"Yeah, I can see! And I heard!" said Sarah, with a giggle. "Hello, sir, are you having a good day?"