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Her name was Jeanette and she was a Ravenclaw. Those weren't the only things that Sherlock knew about her, of course. For example, he could tell that she had two younger siblings, one brother and one sister, and that she favoured her little brother. He could tell that her favourite subject was Charms and her least favourite subject was History of Magic. He could tell that when she graduated from Hogwarts she was going to try to become a teacher and that she would probably do well, would end up in the field of private teaching most likely. He could tell that she liked chocolate and studying and owls, that she didn't like toads, cats or the colour red.
He could tell that she liked John Watson.
"Seriously, Sherlock, if you glare any harder..."
"Piss off," Sherlock said waspishly, not glancing away from where Jeanette and John were smiling shyly at each other. Jeanette had been on her way out of the Great Hall when John turned and, in a move so casual it had to have been practiced beforehand, caught her eye. It hadn't taken much more to coax Jeanette closer and now the two of them were exchanging awkward greetings that made Sherlock's skin itch to contemplate.
"You do know that she's just a student," Molly said helpfully from his other side, which wasn't really very helpful at all. "She and Watson seem quite well matched to be honest."
Sherlock turned his glare on her and, although she did not shrink back into her seat the way she once might have, she fell silent and glanced down at the remains of her meal. Irene just laughed. "You're so pathetically obvious it's adorable," she remarked, reaching out to pat Sherlock on the arm. "Darling, if you want the boy to be yours you're going to have to be a little less subtle about it. I'd wait until after it won't get you fired, of course, but just remember that Hufflepuffs aren't exactly known for being the most clever of the lot."
"Hey," Molly said, sounding a little offended. "I was a Hufflepuff."
Irene arched an eyebrow as though to say her point had been proven. Sherlock just ignored the both of them, refocusing his attention on John and Jeanette. John was always friendly no matter who he was speaking to; it was one of the reasons that he was so widely liked amongst the houses. So it was difficult to tell if this was just his normal degree of friendliness or if there was something more going on. Jeanette was definitely flirting, she couldn't have been more apparent, but John?
The memory of the last few minutes they'd spent together washed over him, stolen in Sherlock's classroom after the rest of John's peers departed a week ago. He'd pressed John down on his desk and, relishing in the sight of John's wide blue eyes, sank to his knees. John had been loud enough to warrant a fresh set of silencing charms and Sherlock knees had ached for hours afterward, but it was well worth it to feel the way John had shuddered underneath him as he came. Sherlock had licked him clean and then stood, catching John's lips in a kiss that made John squirm against him.
That had been only three days ago, and it should have been enough.
It wasn't.
He stood unexpectedly, ignoring both Molly and Irene as he swept around the end of the table and down the corridor between the middle of the tables. John's eyes jumped to him, watching his progress, but Sherlock refused to meet his gaze as he left the Great Hall. Irritation burned under his skin, hot and frustrating. He could imagine John and Jeanette together all too well. Molly was right, the two of them were well matched. Jeanette was patient and sweet, but she also had a stubborn streak and she was more than capable of going toe to toe with John.
His classroom was dark and welcoming and Sherlock shut the door behind him a little more forcefully than was warranted. As he sank down into his seat, he eyed the stack of parchment sitting on the edge of his desk. He was loathe to even begin sorting through it but it was never a good idea to get too far behind; part of the reason he had so much freedom to come and go as he pleased and aid Lestrade was based on the agreement that his professor duties would come first. He tugged the essay on top of the stack over, fetched his quill that wrote with the red ink, and began.
Midway through a decent essay on the properties of dragon's blood, the door cracked open. John entered. His mouth was set into a thin line. He said, "Do you mind telling me what that was about?"
"I have no idea what you're talking about."
"I bet you don't." John sighed and swayed closer, leaning against the front of the desk. "Jeanette thinks you hate her, by the way."
Sherlock pointedly said nothing.
John rolled his eyes, but he was smiling. "Remind me again why I have a crush on you?" he said, fingers curling gently into the scarf that Sherlock always wore around his neck. He was wearing the green one today, a match to his old house colours. He pulled until Sherlock had to tip his chin up or risk being strangled, and then he leaned across the desk and kissed him.
He broke it off only a moment later, exhaling in frustration. "Seriously?"
"You were flirting," Sherlock said.
"And you're being a jealous berk, so I guess we can't have everything we want," John said. He was annoyed now, eyebrows drawing together into a thin line as he stood up straight. "For the past three months we've been sneaking around, even though I'm almost positive that everyone in the damn castle knows that we're fucking. I was just being nice to Jeanette, she's my friend, but if it worries you so much then maybe you should -" He stopped, too quickly.
"Then I should what?"
"Nothing." John turned, took a couple of hasty steps away, and Sherlock moved. His hand landed on John's shoulder and he spun him back around, taking the advantage of his greater height to loom over his student. John wasn't cowed so easily, though, meeting Sherlock's eyes squarely. He looked angry.
"What?" Sherlock said. "You want me to claim you publicly? Make everyone aware that you belong to me?"
"Merlin," John muttered, the tips of his ears flushing pink. "No, you idiot. I just - you're so jealous, so possessive, and I don't mind that. I like that. But I also..." He dropped his gaze. "I hear the way the girls talk about you sometimes. And I just wanted..." He trailed off, squirming a little.
Sherlock cocked his head in understanding, anger giving away to amusement, and he saw the scene from the Great Hall with new eyes. "Were you trying to make me jealous? Are you jealous?"
John reddened, glaring at him. "No more than you are."
There was something appealing about John flirting, trying to make Sherlock jealous, now that he knew it had not been serious. He dropped his hands down to John's hips, thumbs finding their way underneath his shirt. John's breath stuttered in his chest and Sherlock smiled. "You were successful," he murmured, the words emerging in a rumble that never failed to make John aroused. "The thought of you and that girl, of you being with anyone other than me, is enough to make me want to take my wand and cast a few spells that are generally frowned upon by the wizarding world."
"Generally," John repeated, trying not to smirk. "You're not allowed to kill people, Sherlock."
The sound of his name on John's lips never failed to be appealing. Sherlock took several steps back, bringing John with him, until he could sit down in his chair again. John stood before him, blue eyes dilating in anticipation. "Then I guess we'll just have to stay in this classroom for the rest of our lives," he said.
John laughed a little. "You'd go stir crazy in the first five minutes."
"Not if I had a sufficient distraction," Sherlock replied, hands already working at his belt. John's head dropped to watch his progress as he opened his robes and trousers, pulling his half-erect cock out of his pants. Sherlock gave himself a couple of lazy strokes, enjoying the way John's hands flexed unconsciously like he wanted to be the one doing the touching.
What they had was complicated, uncertain at best, and Sherlock was always conscious of the looming fear that someday John might walk away, might find someone better who was closer to his own age. Such thoughts were always enough to make him want to hide John away where no one else could interact with him. That was why here, in the privacy of his classroom, those doubts faded away. All he wanted was John and he was going to have him.
"Come here," he said. "Clothes off."
One eyebrow rose in curiosity but John obeyed, pulling his robes and t-shirt over his head and stepping out of his trousers and pants. He came to Sherlock willingly, tentatively setting his knees on either side of Sherlock's thighs and hovering over him awkwardly. When he sat down, the angle would be just right and judging by the blush on John's face he already knew it. John liked it this way, when he was naked and Sherlock was clothed and he was left feeling open and vulnerable.
"I don't like it when we fight," John said, settling his hands on Sherlock's shoulders.
Sherlock made a noncommittal sound in response and reached around John, picking up his wand. The spell was so familiar to him now he could've cast it in his sleep, covering the fingers of his right hand with clear, already warmed lube. He set his wand down and skimmed a hand lightly down John's backside, the muscles flexing beneath his fingers when he probed between. The initial touch of a finger against his rim made John gasp, the tension melting out of him automatically.
"It's stupid," he went on a little more breathlessly. "I don't want to play those sorts of games with you. I know you're my professor for another couple of months and we can't... you know... until I graduate, but it's frustrating. I just want to tell everyone that you're mine."
"They already know," Sherlock said, pressing his index finger deep. He loved this, the way John wiggled against him with increasing impatience. Both of them were fully hard now and John's cock was leaking against his shirt, leaving a stain he'd cover with his robes later instead of spelling away. He imagined John spending the next class period knowing that and smirked, pressing harder, searching for the right spot.
John groaned, head tipping back, and gasped out, "There's a difference between suspecting and knowing and you of all people should be aware of that. That's good enough, come on, I'm ready."
Sometimes John liked minimal preparation so Sherlock didn't argue, just slicked his cock up and sat back to let John go at his own pace. John steadied himself, breathing deep, as Sherlock lined them both up. He began to ease his weight down slowly, eyes shut and teeth grinding at the stretch. It was tempting to just thrust up and push in deep but Sherlock restrained himself, too fascinated with watching the different play of emotion across John's face.
"I want you to ride me, John," he murmured in John's ear, nipping at the lobe. "So that when I'm teaching your class later and you look up at the front to get instructions off of the board, you'll remember that not thirty minutes earlier you were bouncing up and down in my lap."
"Fuck," John whimpered, sliding down the last few inches. He trembled in Sherlock's lap, hands fisting in Sherlock's robe.
"I know you'll feel it. It burns, doesn't it?" Sherlock traced a finger around John's entrance. It had to ache sharp and deep, but he liked knowing that John would feel him after. Particularly considering that John had practice tonight. He tried not to smile too wide and cupped his hands beneath John's buttocks, urging him up. John went with him, fingers tightening when Sherlock let go and he slipped back down.
It was enough to help him establish a rhythm, though, his thighs shaking with effort as he began fucking himself in earnest. Sherlock groaned softly, squeezing John's thighs. They had never done this before, not in this position, and he was deeper inside of John that he had ever been before. Heated but soft, the feeling of muscles fluttering around his cock, and the sensation was pushing him to the edge much faster than he'd anticipated. He'd known this would have to be fast since class began in less than ten minutes, but it was almost too good.
"Sherlock," John whispered, lips cracked from biting on them so hard, and Sherlock kissed him hard. He pushed John's lips open with his tongue and delved inside, tasting John for himself. John gave as good as he got, tongues twining together messily, both of them moaning as Sherlock's nails scratched their way down John's back.
"On the day you graduate, I plan to fuck you in your gown," Sherlock whispered in his ear. "The second you receive your certificate and I'm no longer your professor. Perhaps I'll join you in the boat, and you can sit in my lap and I'll fuck you as we cross the water. Then everyone will know. Would you like that, John? I could vanish your clothing midway through so they could all see."
John's face was bright red, sweat beading at his temples. He wiggled hard and whined, clenching hard as he spurted against Sherlock's chest. It was too much for Sherlock and he kissed John again as he came, swallowing the sounds of John's cries. The kiss gradually changed from passionate to soft, until Sherlock turned his head and trailed kisses across John's jaw to his ear.
"You are mine," he murmured. "You belong to me, John. Don't try to make me jealous anymore."
"I might have to if this is how you react," John said, grinning mischievously as he squeezed his muscles again. Sherlock's breath caught and John smirked. He leaned forward, wrapping his arms around Sherlock's neck and hugging him tightly. "There's nothing between me and Jeanette or me and anyone else in this school except you. You ruined me for the rest of them and I'm pretty sure I should be angry, because I think you did it on purpose."
"I won't respond to that except to say that I believe you should know the rest of your classmates will be here in the next five minutes."