Teacherlock AU where teacher John puts his mobile number on the syllabus so that if anyone has questions that can’t wait they can text or call and Sherlock Holmes, his smartest and most disruptive student who also happens to be infuriatingly gorgeous texts him every single night, first only simple things about papers and due dates which John knows he doesn’t actually need help with, but they progressively stray further and further away from education and, as guilty as John feels about it, he can’t help himself from responding, and he only makes half-hearted attempts to make Sherlock stop texting him.
They don’t discuss it in class or in person at all, but Sherlock soon takes to sitting on the front row, his eyes heavy-lidded and trained on John, and he’s always wearing ridiculously tight clothing, the buttons on his shirt straining and his jeans so tight John doesn’t have to use any imagination to envision him naked, and it is, to put it mildly, incredibly distracting. Soon the texts at night turn far more inappropriate than John ever intended them to be, and he often spends time that should be spent on grading papers with his hand around his cock instead.
They still don’t talk about it, not yet. Then Sherlock starts spreading his legs wide beneath his desk, and he runs his hands along his own thighs while John lectures, and he unbuttons the top two buttons on his shirt, fingers skimming along the curve of his neck and down into the vee made by his shirt. John puts up with it for as long as he can, which turns out to be a good while actually, a few weeks even, but eventually he can’t stand it anymore, and next class he attached a note to the paper he returns to Sherlock that simply says, “See me after class.”
Sherlock spends the rest of that class smirking, and he remains in his seat until everyone else has left the lecture hall, at which point he gets up and meets John at the front and says, “You wanted to see me, Dr. Watson?” and John, fucking sick of it all at this point, just growls, “Shut up,” and pulls him down into a hard, searing kiss. Sherlock’s muffled sound of surprise is intensely gratifying, and John shoves him back against the wall, already pulling at the fastenings on his jeans and working his hand inside. Sherlock’s head falls back with a moan as John wraps a hand around his cock, and John strokes him hard and rough, Sherlock’s hands scrabbling against John’s back as his knees go weak, and he bites into John’s shoulder when he comes.
Sherlock’s chest is heaving as John eases his hand out, trailing a line of soft kisses up the side of Sherlock’s neck until he reaches his ear where he whispers, “I think we’re done with the teasing, don’t you?” Sherlock just swallows hard and nods, his eyes squeezed tightly shut, and John nips at his ear. “My flat, eight o’clock. Don’t be late.” And then John steps back, picks up his briefcase, and leaves the lecture hall with a smirk on his face despite the incredibly uncomfortable situation in his own trousers. He feels sure Sherlock will take care of that for him later.