This might be putting the condom to good use but it’s also one hell of a terrible idea in general. Anyone can walk past the classroom and sneak a peek in - a student, another teacher, even the principal. And what they’d get would be an eyeful of Derek sprawled in his seat, a dark head bobbing up and down in his lap.
Derek’s eyes dart up to the locked door, Stiles chooses that exact moment to make a displeased noise around his mouthful. His legs twitch, hips jerking up into the teenagers hot mouth. “Stiles!” Derek hisses, fingers detaching from where they’re trying to crush the armrest and sinking into Stiles’ soft hair.
The student hums, a blissed out, happy look in his eyes. He’s wriggling in his place between Derek’s legs and half under the table. Derek guesses that his own erection is starting to get to him. When Stiles lifts a hand off Derek’s hip, Derek immediately presses it back against his abs and whispers, “No touching.” He pushes Stiles’ head further down into his lap.
His body slides down slightly when the teenager goes willingly, hands tugging harder on Derek’s pants until he’s got his hands around warm hips. Derek closes his eyes and sighs, letting himself enjoy this. He tells himself to not think about how dangerous this is, how wrong it is, how Stiles is still a few months shy of legal.
Slim fingers push their way further back, curling around his ass and squeezing playfully. Derek grunts and fucks up into Stiles’ mouth, holding his head in place with his hand. He pauses as soon as his hips return, worried that he might have done overboard. “Sorry.” Derek gasps, fingers petting Stiles’ face and neck.
Stiles pulls away with a gasp, lips and face a rosy pink shade. “It’s alright.” The husky tone goes straight to Derek’s cock. He's the one who made Stiles' voice become so rough. Doubly so when Stiles murmurs, “I like it when you do that.”
He wants to ask what does ‘that’ constitute - choking on Derek’s cock, Derek fucking Stiles' mouth or Derek loosing his grip on his control? It doesn't matter because they all are equally delightful, making him stroke down Stiles’ face to press curious fingertips against his lips. Stiles leans into the touch like an eager kitten, tongue coming out to lick and tease Derek’s fingers.
It’s so easy to feed Stiles more of his fingers, push them against the slick muscle and fuck that pretty little mouth of his. Derek feels his cock throb and smear more precome into the condom covering it, wanting so much to have Stiles mouth back on him. He wishes they had the time and privacy to get Stiles on the desk, face down, ass up, and his dick into the teenagers' greedy little hole. Stiles seems to want the same when he pulls away with a pained groan, head ducking down to give Derek’s cock a hard lick from base to tip.
After that, it’s like Stiles has made it his entire mission in life to get Derek off as fast as possible. His brows furrow in concentration, the top half of his body crowding in between Derek’s legs, heading moving up and down up and down.
"Fuck…" Derek hisses when Stiles’ fingers slip behind his balls and tease the smooth skin there. "Stiles!" His grip goes tight when Stiles whimpers, a tiny little noise that slithers up his spine and breaks his control right down the middle.
The second pained noise that Stiles makes when he realizes that he can’t swallow Derek’s release makes the older man groan throatily because Stiles has said more than once how much he enjoys the act. His cock twitches out the last of his release as Stiles’ whispered words echo in his head. “I like the way I can taste you in my mouth. And the way my throat goes all dry and scratchy like I’ve got a sore throat. Sometimes, I swear it feels like I can still feel your cock in my mouth even though it’s not there you know?”
With a sigh, Derek relaxes into the seat. His hands pet Stiles as he pulls the condom off and begins to clean Derek’s cock with his mouth. Derek groans after the first few licks, his entire body feeling like a set of raw nerve endings. “Stiles…Stop.”
Before Stiles can say or do anything else, Derek pulls him up and kisses him. The teenager all but melts into him, hands sliding up Derek’s chest before wrapping around his shoulders. Before the kiss can turn into something more (like round 2), Derek pulls away to look at Stiles. His stomach twists in arousal - Stiles’ lips are swollen and red, his face flushed, hair mussed to hell. The picture is completed by the erection that’s pushing against stiff denim.
Derek presses his hand against Stiles’ crotch, swallowing down the moan that comes out. He lets the teenager grind against him just until there’s a desperate edge to every roll. Feeling extremely mean, Derek gently pushes Stiles back against the desk and says, “Shouldn’t you be leaving for Chemistry?”
The shocked look Stiles gives him nearly makes Derek laugh. “Shouldn’t you be taking care of the problem that you caused?” Stiles splutters out, waving a hand at his own crotch before trying to straddle Derek’s hips. Derek prevents that by getting out of his chair, moving forward so that one thigh slides between Stiles’ parted legs.
He places a chaste peck on Stiles’ parted lips, murmuring, “Consider that punishment for the condom.”
Stiles’ groan makes a laugh rumble in his chest. “You’re evil.” The teenager grumbles, pushing Derek away. “See if I let you fuck me this weekend.”
Leaning down to pick up Stiles’ discarded backpack, Derek smirks at the younger man instead of answering him, “Smug bastard.” Stiles complains, ignoring the backpack in favor of tucking Derek back into his underwear and zipping his pants back up. “I’m actually going to sexile you.”
Derek’s smirk turns into an amused grin because that’s what Stiles said last week and had barely lasted 5 hours before yelling, “I give up!” and pouncing Derek on the couch. A pretty blush spreads over Stiles’ cheeks as he declares, “I mean it this time!”
"I believe you." Derek offers, still grinning like he won the lottery. "Better be on your way. You can’t go to class with that." He glances down at Stiles’ crotch and leans against the desk.
"Smug, evil bastard." Stiles reiterates before walking out.