Teen Wolf Glompfest (themadkatter13fanfiction tumblr, tagged/Teen Wolf Glompfest) gift fic for anon. Prompt: I'd love me some Monster cock!Stiles and Size Queen!Bottom-Derek. Maybe you could work in someone/s overhearing Derek loudly fall apart on Stiles dick? And Derek involuntarily shifting? I love wolfy Derek.

Thanks to the best friend a girl could have (AO3 users/Monti_B_Lewis) for beta-ing this even though she's so far from being in this fandom that she was confused for half the fic because she was mixing up characters. Any remaining mistakes are my own.

Cross-posted from AO3 a day late.

The loft door hadn't even closed before Derek was on top of Stiles, manhandling him down to the couch with hands as desperate as his was an octopus, arms and legs wrapping around Derek and just generally getting in the way, but right now, Derek couldn't care less. Stiles was back.

"I missed you so fucking much," he breathed between kisses, unable to restrain himself to just Stiles' mouth.

Stiles was just as bad, his soft, wet mouth all over Derek's neck, sucking enthusiastic kisses into Derek's skin. "I hated being away from the pack, away from you." His words were harsh gasps, like he couldn't get in enough air. He probably couldn't, not with how attached his mouth was to Derek's throat. "That was only one semester. College is going to suck."

Derek hummed in agreement as he tugged at the collar of Stiles' shirt to get at his boyfriend's collarbone, eager to get his own marks on Stiles.

The smell of 'others' had faded after a 'Welcome Back!' marathon of the original Star Wars trilogy with the pack, but even having spent the whole time plaster against Derek's side, Stiles still wasn't properly marked with Derek's scent.

Stiles' blunt nails were like claws in Derek's back, tugging and pulling at his shirt until it was peeled up over his shoulders. Derek hissed at the sensation of his skin opening under Stiles' nails, and Stiles huffed a laugh against Derek's neck.

"You can take it, Sourwolf."

Derek scraped his teeth over Stiles' collarbone and grinned at Stiles' quick intake of breath. "I'd like to take you."

All of a sudden, Stiles went still under him, and when Derek realized what he'd said, he stilled too.

"Like… you wanna have The Sex?"

Derek groaned and sat up. "You did not just say that."

Stiles sat up too and pushed Derek onto his back, not even pausing before he climbed on top of him. "It's an important occasion, having The Sex for the first time. It deserves the capitalization, my boring, funless wolf."

"I don't think I want it anymore," Derek said and pushed him off. Stiles fell to the floor with a loud squawk and a flailing of arms that almost caught Derek in the eye.

"Oh come on, don't be like that!" Stiles said indignantly, popping back up. His eyelids lowered and he smirked as he crawled back onto Derek's lap. "I've thought about it a lot, actually. Every night I spent alone in that dorm, I touched myself thinking about you. I'd get off with three fingers up my ass, wishing it was you."

Derek felt the first stirrings of trepidation in his gut as he stopped Stiles' approach with two gentle hands. "Actually, I was thinking about you fucking me."

Stiles' eyes went wide and his mouth parted in a small 'oh'.

"We don't have to," Derek said quickly. "I want to fuck you-"

Stiles jerked forward and their teeth clacked together hard enough that even Derek flinched back. Stiles fell back to the floor with a hand over his mouth and a muffled "Aw fu' 'ha' was sstupi'."

Derek couldn't help it. He started to laugh and there was a pause before Stiles started to laugh too. Slowly, the laughter petered out, and Derek gathered his courage to try again.

"I really, really want to fuck you, but I've been getting off to the thought of you in me since the first time I saw your dick," Derek admitted quietly, eyes fixated on the loft's high ceiling.

"Okay," Stiles said from the floor. "Yeah okay. We can do that. We can definitely do that."

"Jesus, you're huge."

Stiles was blushing under the compliment, but it wasn't false flattery. It would have been hilarious how disproportionate Stiles' dick was compared to the rest of him, but Derek wasn't laughing. He was practically drooling at the thought of having all of that inside him.

Stiles had taken his sweet time fingering Derek open, prepping him slow and easy and with so much lube that the bed below Derek had been soaked. By the time he'd introduced a fourth finger, Derek had been terrifyingly close to losing control and shifting into his beta form. When he realized exactly how close, he'd wrenched himself upright and pushed Stiles onto his back, clambering into his lap and over his hips. Now, with the head of Stiles dick against his hole and the length of it hot and firm in Derek's grip, he wondered if four fingers had been enough.

"You can still change your mind," Stiles said, his voice soft.

Derek looked down at him, to where Stiles' pupils were so dilated, his eyes looked black. He focused on the feel of those slim fingers at his waist, resting on his skin but trembling from the need to grab. "You're not the first big dick I've taken," Derek replied with a haughty smirk.

Stiles' affronted gasp turned into a strangled moan as Derek lowered himself onto Stiles' erection, taking it as slow as he possibly could. It was an eternity until Stiles was completely inside him, until Derek was sitting astride Stiles' waist.

"Oh my god oh my god oh my god," Stiles was chanting, his fingers digging into Derek's waist, his legs twitching as if keeping still was the most difficult thing he'd ever had to do.

Derek would have echoed him the sentiment if he could speak, but as it was, he could barely form a thought beyond 'yes'. He was frozen in place, speared by Stiles, rendered speechless by the sensation of full.

"Derek," Stiles gasped. "If you don't move, I might die."

"Fuck," Derek whispered. He leaned back just enough to place his hands on Stiles' thighs for balance, careful not to put too much weight on the fragile human bones.

"Oh shit."

Slowly, gingerly, he began to ride, rolling his hips with easy undulations of his spine.

He hadn't been lying when he said that he'd been fucked by big dicks before, he actually prefered it, but Stiles was… Stiles. He was everything good in the world and Derek's love for him knew no bounds, and it really was true that an emotional connection did make the sex better.

Or maybe Stiles just had a really great dick. At this point, it was hard to tell.

Derek pulled his feet to either side of Stiles' hips and began to pull up, nearly off of Stiles' dick before lowering himself back down. It was agonizing to go so slow, but so satisfying, to feel Stiles fill him over and over again. His poor boyfriend was trying so hard not to pull Derek down onto his dick, to not fuck up into him the way Stiles so obviously wanted. And Derek loved him for it. Stiles knew everything he'd ever done with Kate, everything Kate had done to him, and he never stopped striving to be the complete opposite. Derek appreciated that with a gratefulness he'd never be able to express.

Every stroke of Stiles inside him grazed over his prostate until Derek could barely breathe he was so hard. It was agonizing, made him want to come so bad, but it was nothing but a slow burn through his veins, and when it was going to come over him, it was going to ruin him.

"Oh fuck, Derek."

Derek hadn't even realized he'd closed his eyes until he was opening them, and he felt a sick lurch in his chest when he realized he was looking down at Stiles's startled expression with the enhanced eyesight of his beta shift. Horrified, Derek slapped a hand over his mouth, over the fangs that had drawn down from his gums. Kate had always been disgusted by the werewolf side of him, had mocked and teased him relentlessly every time it was revealed when he was with her, and though Stiles had never once shown that kind of disdain for him in the past, he'd always been terrified that that would change in the heat of the moment.

There was a hand on his forearm, tugging his hand from his mouth, and Stiles was still staring up at him, mouth and eyes wide.

"That… is so…" Derek cringed- "hot!"

"What?"

"Did you just shift on accident? Is my dick really that good?"

Derek could feel himself blushing, but Stiles never let go of his arm.

"No, seriously, that's amazing. And so hot like fuck I almost came just now, I'm not kidding."

Derek didn't think he'd felt this embarrassed in years, but he'd also never felt accepted in his own skin in his life.

"Stiles?"

"Yeah?"

"Shut up."

Stiles grinned, but stopped speaking. He finally let go of Derek's arm to smooth it down his chest and back to his hip, his grip loosening, more support than encouragement.

Heart in his throat, Derek didn't try to pull his shift back before he started working his hips again. Even with the interruption, his orgasm was still close, and it wasn't going to take much to get him back there.

"You close?" he whispered, resisting the urge to put his hand on himself to help that rush along.

Stiles' eyes gleamed in the sunlight when he nodded, his lips pressed tight together, Adam's apple bobbing in his throat.

"Okay."

Derek leaned forward and wound his fingers in the sheets next to Stiles' head, ducking in for a quick, messy kiss as he began to fuck himself.

"Jesus!" Stiles shouted as he threw his head back, his fingers clenching before loosening again.

"Fuck, Stiles, you feel amazing," Derek groaned, every thrust a spike of fire through his body. "You feel so good, you're going to make me-"

"-make me come!"

Scott stopped dead in his tracks, halfway through the door to Derek's loft, and immediately wished that he'd never been turned just so that he'd never have to hear what he just did. He just needed to get his car keys so he could get away from this building faster than he'd ever gotten away from anything in his life.

Unfortunately, even werewolf speed didn't help him get his keys and get out before he got a good earful of his best friend having sex with their alpha.

"Shit, Derek, you're going to make me come."

Scott paled as the keys jangled in his hand, but nothing could have drowned out sounds that were best left unheard. Someone groaned and he bolted for the door.

"I'm coming. Fuck Stiles, I'm- I'm com- I'm com-"

CLANG

"-ing. Stiles!"

Derek roared when he came, come streaking Stiles' quivering belly, satisfying the beast inside him at having marked his mate.

Stiles, when he came, was silent, curled nearly in half and fingers tight enough to leave bruises.

Derek felt sated in a way he hadn't in years, if ever, and he luxuriated in the sensation, smearing the come on Stiles' skin as he waited for Stiles' mind to come back online.

When Derek finally fell onto his side, dislodging Stiles' now-soft dick, it was to feel come leaking out of his hole and he grimaced. That was one part of the process he could have lived without doing again, if only it didn't mean that Stiles was marking him too.

"I think one of the puppies made the mistake of coming back," Stiles startled him by saying. Derek had been so focused on Stiles that he hadn't heard or smelt anything or anyone else. "I heard the door slam shut. Serves them right for barging in on our sexy time."

Derek groaned and shoved at Stiles' shoulder. "Please stop calling it that."

Stiles chuckled and rolled towards him, curling up in the space under his arm and along his side. "I could come up with something different…"

For a moment, Derek was hit with a flash of all the different, worse things Stiles could call it and let the subject drop.

"That's what I thought. Now, be a good pillow and stay there. I need to sleep after that petite mort. Or should I say 'grande' mort?"

Derek grabbed a pillow and shoved it in Stiles' face. "Go the fuck to sleep."

Stiles, still laughing, moved the pillow under his head, then leaned up to press a kiss to Derek's cheek. "Whatever you want, sourwolf. Whatever you want."

FINIS

The AO3 version contains a link at 'Go the fuck to sleep' to an audio book on YT of Sam Jackson reading that same book (nDGKK6y8OtQ).

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