Note before reading: Mamoru and Usagi are both over 18 in this fic and they're roleplaying a student/teacher relationship, if that is something you would prefer to avoid.

Head of the Class

"Class is now in session. Books away, pencils out – and by pencils, I mean penises. Or is it penii?"

From his spot on the bed, Mamoru glanced up from the textbook he had been studying. His live-in girlfriend Usagi was leaning provocatively against the doorframe to his bedroom, dressed in a pink blazer over what he suspected was a white lace corset top and a body-hugging tan pencil skirt. Her long blonde hair, rather than styled in her trademark odango, had been pulled back in a chic bun at the nape of her neck.

He chuckled. "Usako, what are you doing?"

"That will be Professor Tsukino to you, Mr. Chiba," she said, sauntering further into the room and moving to stand at the footboard.

Mamoru raised his eyebrows, officially intrigued. He bookmarked the spot where he left off and closed his text, setting it aside on the nightstand. "And what subject do you teach, Professor Tsukino, if I may be so bold to ask?"

"Sexology, of course."

He grinned, liking where things were going. "Ah, one of my favorite courses." Certainly a more interesting subject than the biochemistry he had been studying. He started to take off his gold-rimmed reading glasses, but Usagi shook her head.

"No, no, keep them on," she said. "You always look extra studious when you're wearing glasses. Not to mention, like, super-hot."

"Is that really something a teacher should be saying to her impressionable student?"

"Ahem, I'm a professor," Usagi reminded him, crawling onto the bed and straddling his lap. "Totally legal."

Well, perhaps in the sense that both student and university professor are likely old enough to consent, although ethically… Mamoru shook his head. What was he even thinking about at a time like this? Brain off, hormones on.

"Oh, sorry. Well, Professor Tsukino, what is on the lesson plan today?"

"Today's lesson will be on the female orgasm," Usagi announced. "To begin, can anybody tell me where the clitoris is located?"

Mamoru raised his hand, ever the proper student.

"Yes, Mr. Chiba?"

"It's difficult to explain with words," he said. "Would you allow me to show you instead?"

A smile danced across Usagi's glossy pink lips. "Yes, I believe that will suffice."

As an aspiring doctor, Mamoru, of course, knew exactly where to locate the clitoris, but he decided to have a little fun along the way. "Hmm, is it here?" he asked before brushing his lips against Usagi's in a kiss that was far too brief, if her frustrated moan as he pulled away was any indication.

"No, I'm afraid that is incorrect."

"Huh. Well, how about here?" His hand slipped inside her blazer, his thumb stroking in tiny circles against the hardened nipple poking through the lace fabric of her top.

A sharp gasp escaped her lips. "N-No, not quite…"

His other hand began sliding up the inside of her thigh, her skirt riding up. "Then what about here?" he asked, his palm rubbing over the outside of her panties, which were already damp from her arousal. Feeling how much she was turned on provoked the start of his own, the blood rushing down to his lower half.

Usagi bit down on her bottom lip, making a soft whimpering noise at the back of her throat. "So close, Mr. Chiba… You're almost there…"

Mamoru glided his pointer finger underneath the her panties and inserted it inside of her until he found the small nub that provided her so much pleasure. "Here?"

Nodding her head, Usagi let out a moan. "Good job!" she said as he continued fingering her, the tip of his finger circling around her clit with just the right amount of pressure. Her moans got even louder when he brought his mouth to her neck, gently sucking the sensitive skin near her pulse point. "The clitoris is a female, uh, sex organ located at the point where, uh…the labia majora –"

"Labia minora," he corrected on reflex, his lips trailing up her jawline to the secret erogenous zone behind her earlobe.

"—right, the point where the labia minora meet, uh, above the opening of the…mmm…the opening, uh, of – " Unable to recall the word "urethra", Usagi giggled, lightly slapping him on the arm. "Mamo-chan, stop it. You're not being fair! I spent all afternoon memorizing that lesson."

"You know, you sound incredibly sexy when you talk like an encyclopedia," Mamoru said, looking up at her with a cheeky grin, not sorry at all for the distraction. She certainly had no issue with distracting him from his legitimate studies, after all.

"I do?" Remembering herself, Usagi cleared her throat. "I mean, that will be quite enough, Mr. Chiba," she said, pulling his hand out from underneath her skirt. "Now, who would like to demonstrate to the class how to stimulate the clitoris orally?"

Once again, Mamoru raised his hand high in the air, waving it for good measure. "Oo, me! Pick me, Professor! I've been studying real hard!"

He could tell Usagi was struggling not to laugh, her cheeks puffing out as she tried – and failed – to keep a straight face. "Okay, Mamo-ch—I mean, Mr. Chiba. Please come to the front of the class," she said, shrugging her blazer off her shoulders and tossing it in the general direction of the hamper. Of course, being Usagi, it landed nowhere near the basket.

Climbing off his lap, she laid down against the pillows.

Mamoru, after giving her another brief, but lingering, kiss on the mouth, moved the end of the bed, positioning himself in between Usagi's spread legs. He slid both his hands up her thighs and underneath her skirt, pulling it upwards until his fingers wrapped around the waistband of her panties. Usagi's hips lifted a couple of inches off the bed as he tugged the lace fabric down, assisting him until he was able to completely yank them off.

Mamoru inhaled a sharp breath as Usagi spread her legs even further apart, revealing everything to him. "God, you are beautiful," he breathed.

"Flattery won't get you extra credit, Mr. Chiba," she teased, propping herself up on her elbows, "although it is very much appreciated."

"I'll keep that in mind."

After finally taking off his reading glasses – they would only get in the way of what he was about to do – and setting them safely on the nightstand on top of his forgotten textbook, Mamoru lowered himself, pressing his lips against one of Usagi's raised knees. She let out a soft gasp. Encouraged, he began trailing open-mouth kisses along the inside of her thigh, taking his time as he slowly made his way up. At random intervals, he stopped and sucked the skin hard enough to bruise, Usagi moaning at the sensation.

"Mamo-chan…"

"It's 'Mr. Chiba', remember?" he said with a smirk, locking eyes with her only for a moment before switching his attention over to her other leg and starting the whole torturous process over again.

Usagi tilted her head back, groaning in frustration. "Ugh, you are such a tease, Mr. Chiba," she said.

"Just being thorough and making sure I get it right, Professor. I'm aiming for the top of the class, after all."

"Well, you certainly – Mmm… I'm going to have to wear pants for the next few days, aren't I?"

Releasing the suction on her skin, Mamoru pulled back a little and admired his handiwork. There were small pink patches all along the inside of her pale thighs, a few of the older ones already turning a shade closer to purple. "Probably. Sorry."

She raised her head back up, smiling down at him. "Don't be. I like it when you leave your mark on me."

Yes, but Usagi looked so cute in short skirts… He made a mental note to keep that in mind the next time he wanted to mark her with hickeys like some horny high school boy.

Mamoru resumed his trail of kisses up the inside of her thigh until he finally reached the apex of her legs. There, he used the flat of his tongue to lick the length of her slit, Usagi gasping as her head fell back against the pillows.

"Mamo-chan…"

He ignored her lapse in character, no longer caring, and repeated the motion several more times, enjoying the needy whimpers it provoked in Usagi. After a while, he added his fingers to the mix, using them to pry her wet folds apart for better access to the subject of the night's lecture. Her hips bucked when he flicked the tip of his tongue over her clit, Usagi muttering words that would never dare cross his real professors' lips in the middle of class.

"Do you like that?" Mamoru asked, taking a break from his task to lift his head back up. In lieu of his tongue, he let his pointer finger take over, the tip once again swirling around her clitoris.

"Uh-huh," she breathed, her chest rising and falling with her heavy pants. "But I must remind you this is supposed to be an oral exam, Mr. Chiba," she added, getting back into character. "No fingers allowed."

His mistake. "Sorry, Professor."

He removed the forbidden finger and got back to his assignment, burying his face in between her spread thighs.

The growing bulge between his own legs was fast becoming uncomfortable, his erection straining against the fabric of his pajama pants. Mamoru longed to release it, to bury himself inside her instead, but even in fantasy, his pride as an honor student wouldn't allow him to accept the automatic fail Usagi – Professor Tsukino – would undoubtedly give him if he did. He forced himself to ignore it, giving his full attention to the achievement of her pleasure alone.

With slow, deliberate strokes, he teased her, Usagi reaching downward to run her fingers through his hair. Her breathing was becoming erratic, and she began rocking her hips, tiny whimpers coming from the back of her throat. Mamoru, recognizing the signs that she was close to climax, continued at a steady pace, lightly digging his fingers into her thighs.

It didn't take much longer for her orgasm to hit, She gasped out his name, Usagi's back arching off the mattress as she tugged on the roots of his hair.

Mamoru didn't stop what he was doing until he was certain she was finished. At that point, he propped himself up on her stomach, grinning as he looked up at her in expectation. "So, how was that, Professor Tsukino?"

"Mmm, yes, very satisfactory," Usagi said, completely blissed out. She continued playing with his hair, brushing it to the side with her fingers. "You passed with flying colors."

"Well, I did have a very good teacher…"

"Is that so?" Pushing him off of her, Usagi once again straddled Mamoru's lap and began untying the stays on her corset top. A seductive smile crossed her lips. "In that case, would you like to have a private tutoring session after class, Mr. Chiba?"

Yes, he would like that very much.

DISCLAIMER: "Sailor Moon" belongs to Naoko Takeuchi.

AUTHOR'S NOTES: This was written for floraone's Sailor Moon Smutember challenge on Tumblr, Theme: Sex Education/Teach Seduction. It's my first time writing smut for smut's sake, but it was pretty fun! I hope you enjoyed it.

Feel free to follow me on Tumblr! My username is kaleidodreams.