A/N: Kinky smut ahead! Dubious consent! Read at your own risk! This is a work of *fiction*, actual sex without clear consent is assault. Enjoy!
The darkness fed his taste for her. The thing that lurked within him wanted nothing more than to sink it's teeth into her yielding flesh. The sudden bouts of lust at the very sight of her were not unusual, but he'd never had to physically stop himself from slamming her against the nearest wall and fucking her into oblivion before this thing became a part of him. Though he'd Imagingined it enough. She didn't seem to suspect his torrid thoughts, however, and was often to be found in his vicinity since his trip to the afterlife. This night their sanctuary from the world was her bedroom, where they sat surrounded by calculus textbooks. The numbers no longer made sense to Stiles, since Lydia had crossed her legs in such away that he got a glimpse of lace between her sweet thighs.
The wickedness squatting on his soul lifted it's head, eyes sparked like a predator spotting it's prey. Silently Stiles wrestled with the thing, pressing his palms to his eyes until he saw spots. It was a losing battle, and he cursed his own weakness. She swung her legs off the bed and walked over to the window. Rain hit it like bullets and the world was hidden by the night and a howling storm. She was momentarily silhouetted as a flash of lightning filled the room, and in that moment he moved at an inhuman speed, coming to stand behind her.
"Lydia, I think we're done studying."
"I think you're right." She giggled, surprised at his quickness in joining her. She hadn't noticed the edge to his voice. A dark tone that hadn't been there before.
Next thing she knew she was clasped against his chest, arms pinned to her sides, with his hand clamped down over her mouth. She squirmed against him, but his hold was firm.
"Relax." He whispered, his lips at her ear. "I'm not going to hurt you. But if you scream I will punish you. Understand?" She nodded, wide-eyed and clearly confused. He moved his hand from her mouth.
"What the hell, Stiles!" She exclaimed as soon as she was able, attempting to wriggle out of his unyielding hold. "Let me go! This isn't funny!"
He didn't answer, simply brushed her hair over her shoulder, giving himself access to her slim white neck. The monster inside groaned. He leaned in, and pressed his lips into the hollow beneath her ear.
"I'm not trying to be funny." She heard it this time, the growl beneath his words, as his hot breath hit her skin and she felt herself shudder involuntarily. She suddenly became acutely aware of his form pressed hard against her own.
"Wh-whaat the fuck do you think you're doing then?" She'd tried to sound defiant, but her voice cracked when his tongue flicked against her skin. A fire began to spark into life somewhere beneath her naval. His hand snaked it's way down the side of her body, coming to rest just bellow her hip, his fingertips dangerously close to her centre which tingled with misguided anticipation in response.
"Hmm... I'm hurt, Lydia. Can't you tell what I'm doing?" She blushed at his words, something she hadn't been made to do for years. His fingers traveled further south, coming to rest at he hem of her little dress. He caught her ear between his teeth, and she let out a whimper. He chuckled at her reaction, a dark, filthy sound that made her sure that her knees had evaporated and that she was soon to crumple to the carpet. He held her up and purred,
"If you want to play, sweetheart, we can play. But you'll be doing things my way. If you want me to stop, tell me, but know you'll be missing out." He already knew the answer, and wasn't surprised when she made no protest, though she was shocked at her own eagerness to continue. A part of her begged herself to realise just how un-Stiles he was being, but that part was stifled as his fingertips began teasing at the skin just beneath the hem of her dress. Her legs opened by an inch, a silent beg that he give her inner thighs the same treatment. He gave into her desires for a moment, going so far as to hook his finger under the elastic of her underwear. She made a whimper like nothing he'd heard before and he fought the urge to tear them off and push himself into her right then. But he fought it, the demon inside enjoyed anticipation as much as Stiles himself did.
"Did you think I'd indulge you so quickly?" He muttered, abandoning her thighs and finding his way to the zipper at the back of her dress. Trusting that she would not run, and he could move faster anyway, he let her go, tugging down the dresses zip as he did so. He made quick work of the garment. Soon it pooled around her feet, leaving her self conscious and exposed. She crossed her arms over her chest, her attempt at modesty only making her all the more vulnerable a plaything in the wicked thing's eyes.
He circled her like a jungle cat, inexplicable shyness causing her to lower her eyes to the floor, unable to meet his hungry gaze. She could hear the blood rushing in her head, and feel the wetness spreading between her legs. Lydia didn't know why she was letting this happen to her, she only knew that it felt too good to stop. Too good to resist.