Jace turned the page of his book and glanced towards the clock above his door, bored. The sky outside his window was a dark blue-black. It was almost midnight but he wasn't tired in the slightest. Even so, he couldn't focus on the words of the pages; they'd begun to blur together, and he'd read the page over three times now. None of it was processing in his brain.

He tried not to consider the reason that he was restless yet unable to concentrate: he had the whole Institute to himself except for Clary. She was probably asleep, her soft red hair sprawled across her pillowcase. This was the second of the six nights they were being left alone together - a family member of the Lightwoods whom Jace had never met had died, and Isabelle, Alec, Maryse and Robert had left for Idris to attend the funeral. Jace had been offered the opportunity to also attend, but instead chose to stay at the Institute under the pretence of training Clary properly. In reality, he wasn't keen on visiting Idris any time soon and, as much as he hated to admit it, the idea of being alone with Clary for six nights gave him a slightly weightless sensation in his chest.

A soft, tentative knock rapped against his door and his heart thumped in panic, as if she'd caught him speaking out loud to someone about how he felt. He knew it was Clary at the door; he was familiar with the soft sound of her knuckles against his door, and he doubted a demon would knock politely. He instantly patted his golden hair down and adjusted his shirt so that it hung differently on his chest. He realised how pathetic he was being and rolled his eyes at himself.

"Come in," he called softly, setting his tedious book down beside him.

Sure enough, Clary appeared behind his door and smiled shyly before quietly shutting it behind her. Her dark red hair was pulled over one shoulder. He immediately noticed how flustered she looked: her eyebrows were knitted together nervously, her hands were fumbling together and a dusting of scarlet lay across her cheeks. He wondered with a flash of panic if she was ill.

"Are you all right, Clary?" Jace asked worriedly, sitting up.

Clary walked closer, staring down at her fumbling fingers. She took a deep breath and sat on the edge of his bed, as far away from him as possible. Jace raised an eyebrow, perplexed.

"I have, um, a favour to ask," she began, not looking him in the eye. "I-I need some help with something. Something very, very embarrassing, and you're the only person I can trust to help me with it."

Jace pushed down the slight feeling of smugness that rose inside his chest and tilted his head curiously instead. "What is it?"

She looked around his almost-empty room for a moment, her mouth opening slightly. She seemed to consider her words carefully before saying, "I just feel a bit inexperienced."

Jace furrowed his eyebrows, utterly confused.

She stared into his eyes for a moment and then stood as if she was going to suddenly run out of the room.

"It doesn't matter," she told him through a nervous laugh. "I'm being stupid, I should just go-"

"Clary!" Jace said kindly. "You can ask me anything. Go on."

A darker red flush spread over Clary's pale cheeks, and she couldn't bring herself to look him in the eyes. It was odd to see brave, confident Clary looking like a nervous schoolgirl. Staring at her shoes, she continued, speaking very quickly.

"It's just that... I'm sixteen and I've never even kissed anyone. So obviously I've never had... sex or done anything like that, and I'm just... well... scared."

With the last sentence, her bright green eyes flicked to Jace's dark golden ones, anxious and apprehensive.

"Okay," Jace said, the slightly weightless feeling of excitement expanding in his chest. He pushed it down, telling himself not to get too eager. "What are you trying to ask me?"

"I'm not asking you to have sex with me or anything!" she blurted out, as if he'd angrily accused her of suggesting it herself. She kept tucking her thick red hair behind her ears. Jace wondered if he could snatch her hand away without offending her. "I'd just like to have an orgasm."

Jace's eyes, which had been focused on her fingers as they pushed a particularly resilient strand of hair behind her ear, widened considerably and darted to hers.

"I tried to do it myself," Clary said, unsure, "but I can't find where to touch to, um... get myself off." The last three words were a horrified whisper.

Despite his nervousness, Jace felt a self-righteous smirk tugging at one corner of his mouth. "And you need my glorious expertise?"

"Oh, shut up," she said, a small smile tugging at the edge of her lips.

Jace laughed loudly. He decided to play his usual cocky persona and raised his arms above his head in a bored stretch. He was delighted to see her gaze drop to the stretch of skin between his boxers and his t-shirt.

"So, what do you want me to do?"

"I want..." Clary began slowly. Her mouth opened and closed several times before she said, "I want you to show me how to touch myself."

Jace dropped his act immediately; his arms dropped to his sides with an audible slap. They stared at each other for a moment, Jace in disbelief and Clary in trepidation. He couldn't let himself believe this was actually happening to him. It had to be one of his wet dreams, fuelled subconsciously by the knowledge that he and Clary were alone together.

"Show you?" he croaked.

Clary nodded, her curls bouncing around her shoulders.

As delighted as he was, he couldn't help but make sure she was certain. "What makes you think I know anything about that sort of thing? Shouldn't you ask Isab- wait, no. I realise how awful that conversation would be."

"Come on, Jace," Clary pleaded. "I know you know what you're doing."

Jace stared at her for several moments. His heart was pounding in his chest. "Are you sure, Clary?" he asked.

"Well, yeah. Only if you want to, as well! Or, at least, don't mind."

Jace stared at her face with apprehension and excitement.

"I... alright," he conceded. "How do you want to do this?"

Clary grinned at him - a big, warm, innocent smile that made him feel like a bit of a pervert.

"Any way you want, boss."

"Come here and turn around," Jace said, leaning back on his bed so that his back was pressed against the headboard and pillows, his arms held open.

Clary crawled onto the bed before easing into his open arms. Her head rested on his left pectoral, her scarlet hair fanned out across his stomach and shoulders. Her fingers twined together nervously in her lap and she looked up at him expectantly. His arms moulded around her easily.

"All right," he began, trying to keep the nervous tone out if his voice. He tightened his grip around her in preparation. He felt her head against his chest, the crown of her head tickling his neck. He drew a deep breath before speaking.

"First, you've got to tease yourself a little," Jace began, threading his fingers through hers. He pulled their hands up to the waistband of her pyjama bottoms. "Just rub yourself on the outside of your underwear…"

Jace trailed off as she heard Clary's sharp intake of breath. She wasn't even touching herself yet. He moved their intertwined hands underneath the waistband, guiding her hand to the desired location. He paused at this point to look down at her. Her eyes were shut and her bottom lip was trapped between her teeth as she tilted her head back to rest over his thumping heart. He wondered if she could feel how hard it was beating for her. He could feel her fingers rubbing back and forth underneath his. She drew in a harsh breath.

"Are you feeling hot yet, Clary?" Jace breathed quietly against the shell of her ear. A breathy sigh escaped her as she nodded.

"Put your hand inside your panties. Stroke yourself."

Clary hesitated slightly at his blunt words, but did as she was told. A few breathy mewls escaped her.

"Try and find something like a little round bump," he told her.

"I know what a clit is, Jace," she snapped, but not with as much force as she had intended.

"Rub it," Jace said, ignoring her. He was trying hard to control his breathing, to not let her know how aroused he was. He saw her fingers moving beneath her pyjama bottoms, but nothing happened. She out an adorably frustrated growl as she rubbed and rubbed with no result.

"Are you sure you're rubbing the right thing?" Jace asked, looking down around her head to where her hands disappeared into her underwear.

"I'm not sure," she mumbled.

"Can I try?" he asked hesitantly. His question, despite his voice being quiet, pierced the silent room.

He worried for a moment that she'd shove herself away from him, disgusted by him. Instead, a tiny, almost inaudible moan escaped her lips, only picked up by his Shadowhunter ears. He let himself consider the idea that maybe she might be as attracted to him as he was to her.

"Okay," she whispered.

She moved her hand away and he began to lower his first two fingers into her underwear. He suppressed a shiver as his forefinger encountered the wet little button she had failed to find and rubbed it slowly.

A strangled gasp sounded from Clary's lips as her nails dug into the mattress. He could feel that what was once a steadily growing erection was now a large, throbbing hard-on, fighting against the material of his boxers and digging into his jeans.

Jace smiled at her response.

"Now that's what I was expecting," Jace whispered, his lips caressing her neck as he spoke.

"Mmm..." Clary moaned, her hand tightening on his neck. "Jace..." Clary breathed, her tone full of pleasure.

He began to pull his fingers away, but Clary's hand flew from his neck to clamp down on his hand.

"D-Don't move away," she pleaded. "Please could you just… carry on?"

It was like music to Jace's ears. He wasn't quite sure what to make of the situation when he felt her pressing into his hand, a slow rocking motion that was driving him crazy. Her legs tightened around his, forcing him to push back to keep them open.

"Okay," he said quietly.

He swirled his fingers around her fleshy bundle of nerves, each breathy mewl that escaped her throat urging him on. He became braver and braver, even dipping his fingers to trace her slit. He could feel the heat from her hot, wet centre.

"Oh my God," Clary uttered in a strangled tone. "Do that. Do it again."

He stroked her opening again, watching her hips buck against his palm. He moved his fingers back to her clit and began to rub and stroke and pinch relentlessly. He could feel her getting wetter and wetter, her centre becoming almost unbearably hot. Heels digging into the bed, his movements became harder and deeper, leaving Clary keening with ecstasy as he rubbed her. She had never felt anything like this before. Her hips bucked against his, moving faster and faster to match his pace, tension mounting in her until she reached her peak with a loud moan, her entire body shaking and waves of pleasure rolling over her as she tried to keep moving with him.

Her head lolled against his chest as she slipped down his body a little. They were both breathing very heavily.

"Wow," Clary said slowly.

"How was your first orgasm?" Jace asked; he tried to sound cocky but was too breathless.

She rolled over slightly so that her stomach and breasts were pressed against his chest. She looked up at him, her eyes sparkling.

"I want another one," she whispered, a small smile playing on her lips.

"We're going to have to switch positions then, sweetheart."

He flipped them over sharply so that she was laid on her back, her crimson hair fanned against the pillows. She smiled up at him.

Suddenly, his mouth was on hers.

His lips moved against her own with a force that contrasted with the way his thumb gently stroked her cheek bone. He bit her bottom lip, sucked the top one and licked the line between them until they parted, and then his tongue slid across her own. He was rough one moment and soft the next as he shifted so she was sitting across his lap. He brought a hand up to trail through her hair, and the slight scrape of fingertips across her scalp made her gasp. They kissed for minutes or maybe hours, his mouth working her over any way possible.

Jace made a low noise before he shifted to face her fully, and again those golden eyes gazed into hers. "Do you trust me, Clary?"

"I trust you," she told him resolutely.

He leaned back so that he was kneeling and pulled off his white t-shirt, throwing it into some darkened corner of the room. His chest was lean and well-defined, years of training and fighting causing rigid lines of muscle blanketed by golden skin. The way his marks rippled whenever he shifted was enough to make her swallow.

"Your turn," he smirked.

He stripped her of her patterned pyjamas, his lips never leaving hers as he did. When she was left in just her underwear, he leaned back to appreciate the view. Her pale breasts spilled out of the cups of her black and lilac lace bra. He leaned forward and kissed a line between the two mounds and down her stomach as he unclasped the bra. His feather-light kisses stopped as soon as he reached the waistband of her matching underwear. They were soaked. A thrill went through him as he realised he had done that to her. He pulled them down over her hips roughly, stroking her as his hand travelled down to pull them off her legs. His thumbs slightly skimmed the moisture just outside her swollen skin. She let out a moan that turned into a gasp as he pushed her legs wide apart, his face closer to her than anyone else had ever been.

With that, he finally, finally put his mouth on her.

He didn't go straight for her clit, choosing instead to press kisses all over. His lips were swollen from her kisses, plump and soft against where she was aching for him.

"Put your hand in my hair," he demanded gruffly.

She moved her left hand from where it had been holding onto the sheet and propped herself up on her elbows so she could reach his head. She threaded her fingers into his hair, amazed at the softness of it. His hands tightened around her thighs, her high, desperate moan encouraging him to keep moving. He gently took her sensitive clit into his mouth and the feeling made her breathless. Nothing had ever felt like it. Clary was moaning continuously, a feeling of something hot and deep in her belly, intense and throbbing. She was making noises that would usually embarrass her but Jace was staring at her like he couldn't get enough. Jace brought a finger down to her entrance, making sure it was wet before sliding it inside. He moved it slowly, still sucking gently on her clit as he slid his finger further in, and suddenly he touched something that made her hips jerk and waves of pleasure crash over her entire body.

"Jace!" she cried, her body arching of the bed and tearing desperately at his hair. His tongue kept flicking her clit and lapping at her heat until all of the waves and spasms had subsided.

As she laid back, breathing heavily with an arm thrown dramatically across her face, he collapsed onto the bed next to her.

She took his hand and entwined their fingers. Her chest was falling in uneven rhythms, and she tried to regain her breath. He pulled her towards his body, and pressed their chests together. Clary laid her head against the top of his chest, nuzzling her nose into the smooth skin. Jace ran his fingers throughout her hair, while kissing the top of her head, and with his other free hand, he traced intricate designs along her back.

"Well, that was fun," Jace said brightly, pulling her even closer.

"Way to ruin the mood, Jace."

Jace laughed loudly, his fingers never ceasing their journey along her spine. They laid in comfortable silence for a few moments, their breathing getting slower and slower.

"You are so beautiful, Clary," Jace said softly, his fingers brushing her hipbone.

"Thank you," she breathed.

"I hope this wasn't just a one-off lesson, because I don't think I can live without doing that again," he confessed, chuckling breathlessly.

Clary twisted to look up into his face. "Honestly?"