Posted originally on the Archive_of_Our_Own at https://archiveofourown.org/ works/2550701. Rating: Explicit Archive Warning: Underage Category: M/M Fandom: Supernatural Relationship: Castiel/Dean_Winchester Character: Castiel, Dean_Winchester, Sam_Winchester, Gabriel_(Supernatural), Michael (Supernatural) Additional Tags: Underage_Sex, I_guess_it's_underage, Bottom_Castiel, Top_Dean, Mirrors, Weight_Room, Gym_class, Teacher-Student_Relationship, Alternate_Universe -_Student/Teacher Series: Part 1 of No_Longer_a_Crush,_It's_More_of_an_Obsession Stats: Published: 2014-11-02 Words: 3695 ****** The Best Kind Of Drug ****** by LucilovesSamwholovesGabriel Summary Castiel hates gym. Don’t get it wrong, he’s good at sports, like really good, but he hates gym. He especially hates his attractive gym teacher who has no right to be that damn attractive. Dean Winchester. The teacher every girl swoons over, the teacher every boy tries not to check out every time he walks by in those stupid tight red shorts. Castiel would bet his entire fortune that every person who has ever been in that man’s gym class has had at least one wet dream about him and those fucking tight red shorts. Notes This has been beta'd by Halasige she's the most amazing beta ever. I got this idea while in my weight room in my highschool. See the end of the work for more notes Castiel hates gym. Don’t get it wrong, he’s good at sports, like really good, but he hates gym. He especially hates his attractive gym teacher who has no right to be that damn attractive. Dean Winchester. The teacher every girl swoons over, the teacher every boy tries not to check out every time he walks by in those stupid tight red shorts. Castiel would bet his entire fortune that every person who has ever been in that man’s gym class has had at least one wet dream about him and those fucking tight red shorts.   Doesn’t sound so bad right? Hot gym teacher, something nice to stare at all class period, at least it’s better than the creepy old dude who teaches the other gym class. Well for Castiel, he’d much rather have the creepy old dude, who he’s sure would molest him if he had the chance. For whatever reason, Dean decided to make Castiel a sort of star of the class. Dean was picking him for demonstrations, always giving him those dazzling smiles, and giving him candy for best effort at the end of class almost everyday.   Castiel can’t count on his fingers and toes anymore how many threats he’s gotten from girls who have serious crushes on Dean. Hell, he’s even gotten threats from guys. It’s not like he wants the damn attention! Castiel would rather sit in a corner and draw all class period then sit and be Dean’s monkey boy.   Castiel sighed as he pulled on his grey shirt for gym class; thankfully, this was his last class of the day. He was startled out of his thoughts by the sudden slap on his back.   “Hey Novak, don’t try so hard for all of the attention today okay? Some other people would like a shot for Dean’s affections.”   Castiel scowled. Michael Milligan, the quarterback for the school, and one of the most popular people in this hell hole. He also happened to be openly gay. Everyone knew Michael was jonesing to get into Dean’s pants.   “It’s not like I want his attention,” Castiel mumbled.   Uriel snorted behind the two of them. “Who doesn’t want his attention?”   Castiel rolled his eyes and shook off the hand still placed firmly on his shoulder. “Whatever.”   Castiel scowled at the ground. Those fucking idiots, did they really think he wanted to be the center of attention? His brother wanted the spotlight in everything, not Castiel. Castiel was introverted, preferred playing the piano, and drawing in his sketch book all by himself. He would rather stay in the shadows, not exposed for everyone to see.   Castiel ripped open the door, running smack dab into the devil himself, Dean Fucking Winchester. Dean chuckled, holding out a hand to Castiel on the floor.   “Next time, Cas, I suggest you look where you’re going.”   Castiel glared at the offered hand and hoisted himself up, pushing away Dean’s hand as if it had offended him. “My name is Castiel, Mr. Winchester.”   Dean shrugged. “It’s a mouthful to say, I like Cas better.”   Castiel rolled his eyes. “Of course you do, what are we doing today?”   Dean grinned. “It’s a surprise of sorts, head to the weight room.”   Castiel huffed in annoyance, but walked to the weight room, surprised to find everyone standing outside the front door.   “What the hell?”   The few people who had already arrived at the door talked in hushed tones.   “I heard Dean brought in his brother to teach class.”   “Dean has a brother? Oh man, I bet he’s as sexy as Dean is.”   “Oh, he is, I’ve seen him. He’s got the body of a God.” Castiel froze at the sound of his brother’s voice from behind him. Castiel turned to look at his brother, who was not surprisingly, sucking on a lollipop.   “Gabriel, what are you doing here?”   Gabriel shrugged. “Dean and I are tight, and I wanted to see his brother again.”   Castiel rolled his eyes then turned back to the door, reading the familiar sign that was plastered to it. ‘Do not leave the weight room without an adults permission’. Castiel snorted to himself, he’s never seen anyone leave the weight room when Dean was teaching the class.   When the rest of the class showed up, they were all whispering excitedly about the upcoming lesson. Castiel turned towards Gabriel. “What’s his brother teaching?”   Gabriel grinned wickedly, making a loud popping noise as he pulled the lollipop from his mouth. “Don’t wanna ruin the surprise, little brother.”   Castiel sighed. “Gabriel…”   Gabriel shook his head, popping the lollipop back into his mouth as he slung his arm around Castiel’s shoulders. “Nu-uh, you have to wait for the awesomeness that is Sam Winchester, who’s probably the most bendy person I know, besides you.”   Dean snorted behind them as he walked up to the door. “Gabe, I’m going to pretend I didn’t hear that.”   Gabriel nodded. “As you should, no point on scaring your memory for life with the idea of how much I want in your brother’s pants.”   Dean shuddered. “Never again, Novak, never again.”   Gabriel chuckled and pushed Castiel forward. “Oh come on, Dean-O, you talk about how much you want in--”   Dean whipped around and slapped his hand on Gabriel mouth. “Not a word, Novak. Not. A. Word.”   Castiel raised an eyebrow at the two of them, and Dean smiled while Gabriel rolled his eyes, smacking Dean’s hand away. Once the door was unlocked they all walked through, but the first thing that registered with Castiel was the gigantic man standing at the front of the room where Dean normally taught. Second thing he registered was they looked nothing alike.   “Hey there again, Gigantor, long time no see.” Gabriel grinned, his golden eyes suddenly growing intense.   The man, Sam, Castiel assumed, rolled his eyes. “Hello again, Gabriel.”   Gabriel grinned, pushing Castiel forward.   “This is my brother, Castiel, excuse his lack of voice, he’s kind of shy.”   Castiel snorted and watched with curiosity the look Sam shared with Dean. Dean shrugged and Sam’s hazel eyes narrowed before turning back to look at them.   “It’s nice to meet you, Castiel. Dean’s told me a lot about you. You’re a good at the piano right?”   Castiel froze. When the hell did Dean hear him play the piano? Gabriel answered for him. “Maybe one time you can come hear him play Sam-O. He plays during lunch in the music room. Our parents put him through lessons since he was five, and he’s sort of a badass. You should see him at sports though, talk about a winner.”   Sam chuckled pushing his brown hair out of his face. “Dean said there’s not a sport you can’t do. Think you can handle yoga?”   Castiel raised an eyebrow and glanced around the room, noticing all of the mats on the floor. “You’re teaching us yoga?”   Sam nodded. “I convinced Dean it was something you all should learn, and he got the permission for me to teach you guys every Friday.”   “Come on, Sammy, stop distracting my students and teach them your spiritual crap.”   Sam rolled his eyes. “May I remind you that you know how to do this ‘spiritual crap’. Why don’t you two go find mats, and we’ll begin the class. Alright, everyone, we’re going to start with the basics. Dean and I will come around and correct your poses.”   The ‘basics’ were extremely easy for Castiel and Gabriel. Both Winchester brothers complimented Castiel and Gabriel, often turning all the attention on them. While Gabriel preened under the attention, it pissed Castiel off more than it did on a daily basis. There were plenty of other people in the fucking room who were doing just as well as they were, but the Winchesters seemed to only know how to shower people of Novak descent in attention.   Michael, God bless him, seemed to feel the exact same way. “Mr. Winchester, don’t you think you pay a little too much attention to Castiel?”   Dean turned, smiled at Michael and sauntered, yes, he fucking sauntered, over to Michael’s mat in front of Castiel’s.   “Do you think I’m giving him too much attention, Michael? Perhaps you want all of my attention on you, hmm? Well, I wasn’t going to say anything, because, well, quite frankly your pose is completely wrong. Here, I’ll help you fix it.”   In Dean’s defense, Michael’s pose was truly awful, but he really didn’t have to announce it to the whole class. After running his hands over almost every inch of Michael’s body in order to correct his pose, Michael was officially supporting a boner, and Dean had a shit eating grin on his face. Dean leaned down next to Michael’s head speaking loud enough for Castiel to hear, but not loud enough for the entire class to hear his words.   “Feel like you’ve gotten enough attention now, Michael?”   Dean’s eyes flashed up to Castiel’s in the mirror surrounding the room, his eyes filled with lust and a challenge. Just as quickly as it was there, it was gone, the shit eating grin and the cocky bravado back. Dean turned towards Sam.   “I think they’re ready for their next pose.”   Sam rolled his eyes and moved up to the front of the class to demonstrate the next pose. Dean winked at Castiel and went towards the back of the room. “Stay after class, Cas, there’s something I want to talk to you about.” He said to Castiel as he passed him.   Castiel turned and looked over at his brother, mouthing, ‘What the hell do you think he wants?’   Gabriel waggled his eyebrows. ‘Maybe he wants some?’   Castiel rolled his eyes; Dean wouldn’t make a move here in school, if he wanted to make any at all. Castiel glanced at the giant wall mirror meeting Dean’s eyes for a brief moment before looking away. Okay, maybe he would make a move-- Castiel had no idea, really. He’d never really taken a moment to get to know Dean.   Castiel found himself impatiently waiting for the class to end, being so caught up in his thoughts that when a pair of hands landed on his hips, he completely jumped, crashing down onto the floor. The unmistakable sound of Dean Winchester’s laugh came behind him.   “Sorry if I scared you, I was just trying to fix your pose. You’re getting sloppy.”   Castiel glared up at Dean and he smirked back down at him.   “There’s five minutes left, everyone. Why don’t you all go get changed. Have a great weekend.”   Everyone stood, mumbling their goodbyes. Sam walked up with Gabriel, who was ogling the older man’s ass.   “You did very well Castiel; you’re a natural,” Gabriel coughed. “and you as well Gabriel.”   Gabriel grinned up at the larger man who rolled his eyes, a small smile forming on his lips.   “So, Dean, are you going to be monopolizing my brother’s attention for long? ‘Cause I gotta leave for work here soon.” Gabriel said, turning his glance towards Dean.   Dean shrugged. “I’ll just give him a ride home, you can go ahead and leave.”   Almost simultaneously, Sam and Castiel said, “You’ll what?”   Dean raised an eyebrow. “What? A ride never killed anybody.”   Sam narrowed his eyes. “Dean, can I talk to you privately for a moment?”   Without waiting for an answer, Sam stalked off. Gabriel raised an eyebrow at Dean, who shrugged, following his brother over to the corner. Gabriel turned towards Castiel. “Hold out your hand.”   Castiel cocked his head to the side. “Why?”   Gabriel huffed and grabbed Castiel’s hand, slapping a two small packets into his hand. “You can never be unprepared.”   Castiel felt his cheeks heat up in embarrassment, and he hissed, “Lube and a condom? Are you fucking serious right now, Gabriel?”   Gabriel slapped his hand on Castiel’s mouth. “Jesus, keep it down, will you? Just take the damn thing so I know at least you’ll be safe.”   Castiel glared at his brother. “Who the hell do you think I’ll be using this with?”   Gabriel glanced over at where Dean and Sam stood speaking in hushed whispers with defensive looks on their faces. “Well if I had a guess, he’s wearing bright red shorts right now.”   Castiel blushed bright red.“He’s my teacher, Gabriel.”   Gabriel shrugged. “Never stopped people before, and besides you’re eighteen, so it’s perfectly legal.”   “What’s legal?” Dean asked walking up to the two brothers.   Castiel blushed even harder, and looked away, shoving the two packets deep into his pocket while Gabriel just laughed. “Cassie and I were just talking about him being 18 and being legal.” Gabriel said in response to Dean’s question.   He grasped Castiel’s shoulder. “I’ll see you at home, little brother. Hey, Gigantor, wait up, I’ll walk you out!”   Castiel scowled after his brother as he caught up to the younger Winchester who shut the door firmly behind them. Dean cleared his throat. “So, what did you think about what Michael said today? Do you think I’m giving you too much attention?”   Castiel straightened his spine and looked up into those green eyes that captured so many. “Well, you certainly draw a lot of attention to me on a daily basis.”   Dean took a step closer. “Do you not like the attention?”   “I’m not my brother, I’d rather not have all their eyes on me.”   Dean took another step closer, their bodies only a few inches apart. “Let me rephrase the question, do you not like my attention?”   Castiel searched those green eyes of his teacher for a reason behind the question, only to find mild curiosity in them. “No, I suppose I don’t mind your attention.”   Dean’s eyes flashed with excitement and want. “You mean that, Cas?”   “My name is Castiel.”   Dean chuckled. “Yeah whatever, Cas.”   Dean’s hands cupped Castiel’s face, kissing him gently at first, then deepening the kiss when Castiel began to respond. He kissed back much dirtier than Dean had expected. Dean wrapped his arm around the younger male’s waist, pulling him tightly against him while his other hand wrapped into Castiel’s dark hair.   “Wanted you for so long, Cas, not a day went by that I didn’t want you.”   Castiel pulled back, his breath ragged and uneven. Castiel knew this should feel wrong, Dean was his teacher, and no matter what Dean or him felt, even if they felt anything, they shouldn’t be doing this.   “Dean, we really shouldn’t be doing this.”   Dean sighed. “You don’t think I don’t know that? I know about 90% of the class wants in my pants and the other 10% is in denial. Hell, there are teachers here who have warned me of getting too close to students because of how good looking I am. The thing is, Cas, I’m tired of denying the want I have for you. The reason I put you on display to the class is because I want them to see how amazing you are. I, for whatever reason, thought that if I always put you on display like I have been others would stay away from you because I made you stand out so much.”   Castiel snorted. “Well, that backfired, people would threaten me to stay away from you.”   Dean chuckled. “The things people do over an infatuation.”   Castiel cocked his head to the side. “Isn’t that what I am, though, Dean? An infatuation that you have?”   Dean hesitated for a moment. “At this point, Cas, I would almost say you’re an obsession. You’re like an infection plaguing my thoughts from the moment I wake, to the moment I sleep. I don’t want to fight this craving for you anymore, be with me just this once, Cas, and if you don’t like it or don’t want to take the risk I’ll leave you alone. All I’m asking is for just this once, then you decide.”   Castiel couldn’t deny he wanted Dean, just like every other person who ever entered his class wanted him, but he had to wonder. If he agreed to this and found he wanted more of Dean, if Castiel truly got to know Dean could they be something more?   Castiel met those green eyes that held his so passionately and nodded. “Okay.”   Dean’s eyes lit up triumphantly. “You won’t regret this, Cas.”   The moment Dean’s lips collided with his, Castiel knew he couldn’t regret this even if he wanted to. Castiel twisted his fingers into Dean’s hair, moaning into the kiss, preening when Dean groaned out his nickname that he only pretended to hate.   Dean pulled back suddenly. “Jump,” Dean murmured, catching Castiel as he wrapped his legs around the older mans torso. Dean walked till Castiel’s back hit a mirrored wall, Dean kissed him fervently, massaging Castiel’s dick through his sweat pants.   Dean pulled back, both of their breaths coming rapidly and uneven. Dean stuck his hand in Castiel’s pocket, pulling out the lube and condom packet, grinning down at the younger boy.   “Gonna fuck you up against this wall, Castiel, and no matter where you look you’ll be watching me pound into the tight sweet ass of yours.”   Castiel shuddered, his breath catching in his throat, anticipation settling deep in his stomach. “Well, what are you waiting for, old man?”   Dean snarled, letting Castiel’s legs drop abruptly from around his waist before whipping Castiel around and slamming him up against the mirror. “Be careful, Castiel, I’m only 27.”   Castiel gasped as Dean’s hand suddenly wrapped around his aching cock, pumping him quickly. Castiel turned his head straining to look back at the older man behind him. “Still 9 years older than me. That’s almost a decade.”   “Shut up, Cas,” Dean snarled, slamming their mouths together. Castiel moaned as Dean bit down on his lip and pushed his knee in between Castiel’s thighs to spread them. Dean pulled back, his green eyes almost completely lost to the black of his pupils. Dean gripped Castiel’s pants with one hand, ripping them down sharply, the other keeping Castiel pushed up against the wall.   “Don’t move.”   Castiel watched in the mirror as Dean ripped the lube package open with his teeth, Dean’s eyes ranking down Castiel’s back side. Castiel shuddered as the cold slick of lube teasingly circled his hole.   “You ready, angel?”   Castiel groaned at yet another pet name Dean had come up for him.   “Just open me up already--fuck!” Castiel cried out suddenly as a finger breached his tight hole.   Castiel glanced up at Dean’s predatory gaze in the mirror, whimpering at the want he saw in it. Castiel moaned as the finger inside him twisted, brushing his prostate. Dean grinned against the skin of Castiel’s neck, peppering kisses along his shoulder as he added another finger.   “You’re so tight and hot, angel, can’t wait to be inside you. Gonna fuck you so hard. You’re going to feel me for days.” Dean said as he added a third, hitting Castiel’s prostate repeatedly.   Castiel groaned, resting his head against the mirror, breathing heavily as he fought against the heat pooling in his stomach.  “Fuck, Dean, I’m gonna...”   “Go ahead, baby, no one’s stopping you.”   Dean sucked a bruise into Castiel’s skin as his muscles seized up as an orgasm tore through him. When Castiel came down, his vision slowly coming back to him, he whimpered at the overstimulation to his prostate.   “Dean…”   Dean kissed the skin behind Cas’ neck, shushing him while withdrawing his fingers.   “S’okay, angel, I’ll take care of you.”   Castiel was surprised to find that Dean ignored his own straining erection in favor of letting Castiel come down from his orgasm. Kissing and sucking along his back as his hands wandered over Castiel’s body, adding enough pressure to almost have a massaging effect.   Dean nuzzled against Castiel’s neck a few minutes later, whispering. “You ready now baby?”   Castiel nodded and watched the Dean in the mirror open the up the condom packet much the same way he had done with the packet of lube. Castiel groaned as Dean’s cock slowly breached his hole. When he had thought of Dean having sex he’d never imagined he would be as gentle as he was currently being. He’d expected him to be rough and quick like he’d started out, but Castiel found himself enjoying this side of Dean much better.   When Dean bottomed out, he groaned against Castiel’s back, thrusting shallowly a couple of times, as if to test it out. “You ready, Cas?”   Castiel groaned in frustration, his cock already half hard again. “Dean, just fucking move!”   Dean chuckled. “Your wish is my command.”   True to his word before, there was nowhere Castiel, looked that did he not see Dean plowing into him from behind. Castiel watched in fascination, observing that if he angled his head right, he could see the way Dean’s leg muscles were pulled tight and how his back muscles rippled with every movement.   Castiel cried out suddenly when Dean angled his hips a certain way that hit his prostate dead on.   “You like that, angel?”   Castiel moaned in response when Dean hit his prostate again and again bringing back the burning heat in the pit of his stomach. “Fuck, Dean, I’m so close again.”   Dean's breathing picked up. "I know, baby, so am I. Fuck, Cas, you're, so tight. I could stay in you forever."   Castiel breath hitched before another orgasm came over him. He felt himself tightening around Dean who swore behind him, coming seconds after him. Castiel slumped against the mirror, letting Dean hold him up who was shaking behind him with the effort. They stayed like that till their breathing evened out and Dean pulled away, grinning down at the younger boy.   "So, Cas, you want out?"   Castiel wasn't fooled by the cocky grin, he could see the fear in Dean's eyes. Castiel smiled lazily up at Dean. "I think I could stick around for... awhile longer. After all, I just had the best sex of my life."   Dean's face lit up as he pulled Castiel against him, kissing him like Castiel was the key to living. "You'll be the death of me, Cas."   Castiel grinned. "Then I must be one hell of a drug."   Dean laughed, kissing Castiel chastely against his lips. "The best drug."   End Notes So what did you guy's think? Loved it? Hated it? Let me know in the comments below! Please drop_by_the_archive_and_comment to let the author know if you enjoyed their work!