Hey guys! This is based after the City of Glass, (Book 3), after they finally return home. (I have read all the books, but this seemed like a good place to start.) This is my first fanfic on the Mortal Instruments and also my first time writing a sex scene, and I really hope you guys like it! I tried to keep them in character and actually make it seem realistic. Reviews are appreciated! May or may not be continued.

Lightning illuminated Clary's room casting shadows of her curtains onto the walls. Thunder cracked outside, and with a gasp she shot up out of her bed. Her heart settled quickly after realizing it was only the storm that had woken her, but she could still feel the lump in the back of her throat.

Everything was over. The war had been won. Valentine was gone. Though, knowing all that, she was still finding it hard to sleep even though several days had passed. She was more exhausted than she had ever been. She shook her head in a feeble attempt to clear her mind. She wondered if this was what it was like for soldiers who had just returned from war. The constantly feeling on edge, alone, scared... She immediately dismissed the thought. She wasn't a soldier, no... not like them.

She pulled the covers back and swung herself out of bed. The stone ground was cold on her bare feet, and she shivered as she went to shut the window which was currently letting in a constant cool breeze. The rain was coming down hard, blocking out the normally beautiful view from the institute's higher floors. She sighed as the window locked into place and the room went quiet and still.

She thought of Jace, peacefully asleep in his room a little ways down the hall. She always found it cute when he was asleep. The normally stern and composed look he always carried turned into something more vulnerable and softened and delicate. She had even caught him drooling one day, though he'd never admit it. But all she could think of right then was going to him, and curling up beside him, and listening to him snore blissfully, so that maybe she could fall asleep too.

But her mother and Luke were right down the hall. They had a meeting with a group of other shadowhunters at the institute and decided to just stay there instead of going home in the rain. Of course Clary had to sleep in a separate room than Jace. If Jocelyn found her sneaking into her boyfriend's room at this time of night, she'd never be allowed to stay the night again, but the loneliness and the quiet was getting to be too much. She half ran to the bedroom door and slowly pulled it open, wincing as the creaking echoed down the hall.

She stepped out into the hall and shut the door as quietly as she could behind her. The hallway was almost completely dark besides one flickering lamp at the end of the corridor. It was substantially colder than it had been in her room, and her thin pajama shorts and t-shirt didn't offer much warmth. She almost screamed when she heard a raspy, howling sound. She whipped around to see Church eyeing here suspiciously from a few doors down. He purred contentedly at having caught her and almost given her a heart attack. She put a finger up to her mouth and mouthed "shut up" at him. With a flick of the tail, he staggered away from her.

She tip toed to Jace's bedroom door and stopped nervously in front of it. What if she woke him up? She wanted to lay with him, but hadn't thought of what'd she do if he woke up with her next to him. She was sure he wouldn't mind, but still she felt a little uneasy. But the thought of going back to her own silent, dark, and unwelcoming room almost made her sick to her stomach. She sucked in a breath and reached for the door handle.

Before she had even touched it, the door slowly started to creak open. She felt her heart stop. A tall figure in long pinstriped pajama pants and a loose white t-shirt appeared in front of her. He looked down in bewilderment.

"Clary?.." He whispered in awe.

"Um.. hi, Jace." She sputtered nervously.

"What are you doing here?" He asked with no resentment in his voice.

"I- I couldn't sleep. Where are you going?"

"I couldn't sleep either." He answered truthfully. "I was going to go see you."

She felt herself blush, and she was glad it was too dark for him to see it.

"Looks like we had the same idea, but I didn't think you'd be awake." She whispered.

"Well, come on in. Standing in the hallway probably isn't the best idea." He said with a small smile.

She went inside, and he shut the door silently behind them. For a moment they just looked at each other. Then he pulled her close to him and she rested her head on his chest. It was a relief to be in his arms, taking in his scent, feeling the familiar muscles under his shirt. She breathed blissfully.

"Why can't you sleep?" He asked while running his long fingers through her hair. There was a small hint of worry in his otherwise composed voice.

"I don't feel right in that room. I just.. I figured if I could come lay with you that it'd help me sleep."

He grinned a little and pulled away from her. He plopped down in the middle of his bed and patted the space next to him for her to join him. She snuggled up next to him and laid her hand across his chest. She listened to his even breathing, his heartbeat through his shirt. For once in a long time, she felt relaxed.

"You know, if my mom catches me in here we're gonna be in big trouble." She said jokingly. Though, there was real concern of that actually happening.

"Well, let's not get caught then." He chuckled.

"That should be easy. I mean, how much noise could we possibly make cuddling?"She said, and she felt him laugh under her hand.

She sat up and looked at him. He raised an eyebrow at her.

"What's so funny?"

"Unless cuddling wasn't the only thing you came for." He answered vaguely.

She raised an eyebrow at him too. Well, at least she tried to. She wasn't very good at it.

"I mean come on. Girl sneaks into boy's bedroom in the middle of the night cause she can't sleep, cuddles up to him. I know I'm handsome and all, but am I that hard to resist?" She knew he was just being cocky and was messing with her, but now that she thought about it, it did seem kind of suspicious.

"A bit full of yourself aren't you? And you were about to do it too before I beat you to it!"

"That's because you are that hard to resist." There he goes again, always knowing exactly what to say at exactly the right time.

She smiled and she was pretty sure she was blushing. She could hardly believe that she, of all people, was the one he couldn't resist.

"Oh, really? Prove it."

He grinned and pulled her on top of him. She looked down at him, at those big golden eyes that had captivated her from the moment she saw him. He lifted his head and rubbed his nose on hers with a smile.

"You're all I want." He whispered. "I love you."

"I love you t-"

Before she could finish, his mouth was on hers. One of his hands reached around and his fingers tangled themselves in her hair while the other gripped her side tightly. She responded by gasping a little and pressing her lips to his. Their lips parted and closed in precise synchronization. He sat up so that she was straddling him, and she reached around to where her arms were trailing his back. He did the same, but then he pulled her tight to him as if no amount of closeness was close enough. Her breath hitched when his hands slid down to her waist. Everywhere they touched felt as if electricity was passing through them.

"Now, this isn't helping me get any sleep." He groaned.

"I don't even think I'm tired anymore." She breathed. It was true. Her whole body felt energized and awake. Her heart raced in her chest. She felt alive, unlike any other time before. Even past make out sessions had never felt like this. No, this was something more. It felt hungry, feverish, and more exciting than anything she'd ever experienced.

Without really thinking, she reached down and pulled Jace's shirt over his head. She gazed down at the hard, scared surface of his chest. He caught her staring.

"Clary?" He breathed. "Not that I mind what we're doing, but what exactly are we doing?"

She met his gaze, and to be honest she wasn't exactly sure. Whatever it was, she loved it. She didn't want to stop. She wanted more. And from the rate at which Jace was breathing, she could tell he felt the same way.

"I- I don't really know. Do you want to stop?"

He gave her a questioning look. "Of course not. I could kiss you all day, every day, and never get tired of it. Do you want to stop?"

She shook her head. "No, I love kissing you."

"Do you want to keep going? I mean, passed just kissing?"

Her heart skipped a beat. Was he really asking what she thought he was asking? She stared at him with wide eyes, not knowing what to say.

He paused. "We don't have to. I don't want you to feel uncomfortable."

He ran his hands up her arms to her shoulders in an attempt to sooth her, but she pushed him back down on top of the bed. Her heart raced in her chest, the blood flowing through her urged her to keep going. With a sudden surge of confidence and courage and a bewildered look from Jace, she lifted the hem of her shirt over her head. For a moment he just stared at her, and suddenly she felt a little self conscious. Until he spoke, that is.

"Well, I guess that answers my question."

She leaned down and kissed him again. He pushed her to the right of him so that they were laying side by side. Their hands roamed each others bodies as they kissed. Her hands ran up and down his chest, traced his scars and trailed his back. His gripped her hips and felt her curves, and he reached around her back and found the clip of her bra. He paused for a moment as a subtle request for permission. She nodded and gasped when her bra came loose. He plucked it off of her and tossed it aside, then studied her open chest with a slightly gaped jaw.

"By the angel, you are beautiful..."

He kissed her again, but this time it was slower and more passionate. At the same time, his hand slid up her side, and her heart pounded against her ribs when it stopped just below her breast. She felt him grin, and she knew he was up to something. He was teasing her.

He slid his hand up suddenly and grasped her in his hand. She gasped, loudly, and he grinned again before beginning to kiss her violently. They both sat up as if on cue and he gripped both her breasts in his hands and moved them in a circular motion. She moaned quietly into his mouth, not even really realizing she was doing it, when he took her nipple and squeezed it gently.

He pushed himself on top of her, and she let him without much hesitation. He slid his hand down her bare chest, to her stomach, and paused when his hand reached the waistband of her shorts. She nodded slightly knowing that he was waiting for her permission. She leaned her head back as his hand slipped into her underwear. His fingers felt around for a moment before he slid one inside her. When she didn't seem to be in pain, another one followed.

Her breath hitched. Her face flushed. She had never let anyone see her private areas let alone touch them. She laid there at let him finger her. He stopped for a moment and pulled her shorts and underwear off, then continued. It seemed like an eternity for her, but it had only been a few moments. He didn't seem to mind. In fact, he enjoyed watching her move with the rhythm of his hand and her back arch in pleasure. Even the moans and little gasps she made brought a grin to his face.

He slipped his fingers out of her and wiped them on the sheets.

"You're messy." He said as he smiled and wiggled his still wet fingers at her mockingly. He grinned a devilish grin when her face turned blood red. "Now, its your turn."

She breathed heavily for a moment and let her thoughts return. She leaned up and kissed him, and he melted into her. He gripped the edges of his pants and pulled them down along with his boxers. He shook them the rest of the way off, and she stared at him while he did it. She could feel the blood rushing to her cheeks as she took a look at him completely naked. He really was gorgeous, and she wasn't at all disappointed at his "size" either.

He braced himself between her legs and looked down at her face. Their eyes connected.

"Are you ready?" He asked. His joking tone was gone. The serious, composed Jace had returned.

"Yes." She whispered.

Then, he positioned his body and used his hand to guide himself to her. His gasped as he slid inside her. He moved slowly, because he knew it was her first time. She wasn't going to enjoy it at first, and he didn't want to hurt her more than he had to.

She gripped the sheets and held on to his back for reassurance. It wasn't as bad as she had originally planned. It was a dull constant pain, more like pressure than anything. He nestled his face into the crook of her neck and pushed in and out very slowly. She was grateful he hadn't just shoved it in there like some of the stories she had heard at school. She knew it felt better for him, and she was glad he got to feel good.

Then, the pain started to subside, and she felt her body loosen. Her once tightly balled fists relaxed. She still felt the slight pain, but it wasn't the biggest sensation anymore. Her legs felt numb and shaky. It was starting to feel like sex was supposed to feel like. Intimate. Pleasurable. Intense. She let out a small moan.

He noticed immediately. He picked up speed and let his body take over. His whole body was tense, his mind focused, and every inch of him was tingling with pleasure. He grunted as he began to quicken his pace once again. Her fingers scraped his back every time he pushed back inside her. She was moaning every few strokes now.

Finally, it was getting to be too much for him.

"Clary, I'm close.."

"Go ahead." She breathed reassuringly.

His face tightened as he thrust his hips a few more times. He pushed one time, hard, and his whole body tensed before he came. For a second, he just sat there laying on top of her, trying to regain his breath. Then, he flopped down on the bed beside her. He hadn't felt that relaxed in a while. She swallowed, caught her breath, and looked over at him.

He looked back at her, into her eyes. He was still breathing pretty heavily. She smiled.

He climbed back to her, and she wrapped her legs around his. He felt her heart through her chest as he laid on top of her. For a few seconds they just laid there in total bliss, and stared into each others eyes. He put his forehead to hers and smiled back. He kissed her nose, and she giggled.

"I love you, Clary." He whispered.

"I love you too, Jace."

Alright guys! Thanks for reading! Make sure to review! I would appreciate it!