Author's Note: Hello all! I have spent the last few months reading The Mortal Instruments, and let me just tell you, I have fallen head over heels in love with these books! The story and characters are all beautiful. The couple I have fallen in love with the most, however, happens to be Simon and Isabelle. This is a fluffy lemon that I wrote about their first time. I imagine it being set somewhere during City of Lost Souls. It isn't really anything special. Just some happy little fluff. Sizzy forever. :3

DISCLAIMER: I do not own The Mortal Instruments.

Vixen

by savemesalzburg

"Isabelle?"

It was getting late, nearly one o' clock in the morning. Isabelle Lightwood had forced herself to sit through a nearly twelve-hour Star Wars marathon, after much begging, for the pleasure of her dearly beloved Simon Lewis. The irresistible Shadowhuntress wouldn't be caught dead watching it, and maybe even enjoying it a little bit, in front of anyone else. And, by the Angel, if Simon told anyone that she had sat through this twelve hour nerd marathon with him, he would spend the rest of eternity wishing he was dead.

Well, more dead than he already was.

Actually dead.

She finished tying the belt of her black velvet jacket. It was her favorite winter jacket, both warm and tight enough to hug and accentuate every single curve. Beneath the jacket, she wore a lavender corset and black miniskirt, with long black boots that came up to her mid-thigh.

"Yes, Simon?" she asked, only half listening as she pulled a pair of black leather gloves onto her hands.

"Iz, will you stay with me tonight?"

Isabelle wheeled around to face Simon. Of course, he had to wait until after she had put all of her winter clothes on to ask her. For a moment, she considered saying no. She would receive an earful from her mother in the morning, should Maryse catch her doing the "Walk of Shame" back into the Institute. But how was that fair, when Alec basically lived with Magnus? Isabelle believed one night without coming home without the wrath of the Angel being brought down upon her was justified. Plus, she owed it to Simon. How many times had he stayed with her without complaint when she asked him to?

"Yes, alright," she said, slipping her leather gloves off and placing one in each of her jacket pockets. "I'll stay with you." She untied the belt of her jacket and shrugged it off of her shoulders, hanging it on one of the chairs along Jordan's counter. He and Maia had gone to bed nearly two hours ago, although, Isabelle suspected, they had spent a good hour and a half of that time not actually sleeping. At her affirmative response, Simon smiled and offered her his hand to lead her to his bedroom. He switched off the livingroom light on the way, leaving the two in almost complete darkness. Simon could see perfectly fine due to his excellent vampire night vision, but he knew without a rune, Isabelle was almost completely blind in the dark. He made sure to be extra careful guiding her into his room and down onto the edge of the mattress that he slept on every night. Well, at least the nights that he actually spent here.

Once she felt the mattress safely at the backs of her knees, Isabelle sat down and began to unlace her boots. As much as she loved to wear them, she couldn't hold back a relieved sigh as they slid off of her legs and onto the floor. She silently thanked herself for shaving this morning, her long, slender legs remaining silky smooth even at this hour. She and Simon slid into bed together, both still wearing their clothes. They rolled on their sides to face one another so that their chests were pressed together. This close, even in the darkness, Isabelle could see the smooth details in Simon's face, and the dark color of his eyes. She raised her hand and gently placed it on his cheek, an act which he took as an okay to gently press his lips against hers. One hand reached around to the back of her neck, his fingers knotting themselves in her soft black hair. He could smell her gardenia perfume and vanilla shampoo, the sweet scent of her skin, and even sweeter scent of her blood beneath. Of the three humans he had fed from, Isabelle's blood had tasted the sweetest. She had worked her way from his mouth down his neck, her warm lips pressing against his jaw, then his chin, and finally his neck. She kissed and nipped and breathed around his ear, before settling on kissing an area of skin right beneath his earlobe.

"Simon," she whispered in his ear after she had finished sucking on his neck long enough to give him a decent-sized hickey. Fortunately, or possibly unfortunately, his vampire healing would make the mark disappear in a few minutes.

"Hmm?" he grunted, only half paying attention due to being partly lost in the bliss that making out with Isabelle left him in.

"Will you bite me again?" she asked.

"HMMM?" he grunted again, this time louder and with more alarm. He was pulled completely out of his previous bliss, almost as if someone had dumped a bucket of ice water on him.

"Will you bite me again?" she enunciated her words more slowly and clearly the second time, following up with, "I thought it was really...hot last time." Isabelle Lightwood, for once in her life, sounded sheepish. Simon was reminded of the way Izzy had reacted to his bite last time, moaning and arching her back and losing herself in complete ecstasy. He had to admit, the idea of her doing that again excited him, a lot.

"If...that's what you want," he said, a little unsure. While he wasn't hungry, he wasn't quite sure that he trusted himself when it came to Izzy's blood. He did trust himself enough to stop if things got out of hand, however. The last thing that he would ever want to do would be to hurt her in any way. Especially due to this. Without a second thought, Isabelle turned her head to the side and brushed her hair out of the way, giving Simon a clear shot to her neck. He crawled on top of her, placing a knee on either side of her perfect waist and a hand on either side of her head. He leaned down, first to lightly kiss the smooth skin of her neck. The kiss caused Isabelle to shudder. It was a tender gesture that she hadn't quite been expecting. Simon's fangs shot out, and beneath him he felt Isabelle tense in anticipation. He stole a glance at her, admiring the rapid rise and fall of her chest, and the pallid contrast of her skin to her ebony hair, which fanned out beneath her on the pillow like a dark halo.

Then he bit her, his fangs sinking into her throat, tasting her sweet blood as it rushed into his mouth. He managed to linger there for only a few moments, pulling away and licking her blood from his lips. Two tiny holes, each with its own small trickle of blood, were all that remained. She was left breathless, her chest heaving within the constraints of her corset.

"Bite me again, Simon," she begged, gesturing with a slender, calloused finger to her collarbone, right beneath the chain of her pendant. He kissed her finger before moving it out of the way and obliging, sinking his fangs into the flesh beneath her collarbone.

"Oh, Simon!" she cried. "Bite me again!" She turned her head to the other side, offering him her throat again. It was obvious to see that Izzy was getting off on his bites. And, quite frankly, Simon was getting off watching the way that she reacted to him. He bit her again on the other side of her neck, and several more times on her collarbone and shoulders in response to her insistent moans.

"Simon," she whispered, after what he thought was the seventh or eighth time. He had lost count. "Simon, now I want you to fuck me." His fangs retracted, and his eyes met hers, a look of bewilderment on his face.

"Really?" he asked quietly. "You know, I've never actually done that before..."

"Neither have I..." Izzy hesitated, and then continued with, "Well, alright, at least not with someone that I loved." The room was dead silent. His sensitive hearing picked up only the sound of Izzy's racing heart, although it was beating so hard that he was sure he would be able to hear it without his hearing. Hell, if Simon's heart was still beating, he knew she would be able to hear it racing, too.

"Do you love me, Izzy?" he asked, falling back onto his knees and pulling her onto his lap, placing his hands on the small of her back to support her. She placed her hands on his shoulders and flipped her hair over her shoulder. Her eyes found his in the dark, red lips curving into a smile.

"Yes, Simon. I love you." Dead silence again. He looked at her, studying her beautiful face in the dark, his eyes following the curve of her neck, half to admire her beautiful body and half to make sure that she wasn't still bleeding.

"I love you too, Isabelle," he said, once his eyes met hers again.

Her black eyes grew tender as she studied his face and cupped his cheek in her hand. He moved one hand from the small of her back to the back of her neck, pushing her face towards his as he pressed his lips passionately against hers. Isabelle threw her arms around his neck, licking his lips and sliding her tongue between them. She tasted what remained of her blood on his lips. The hand that still remained on the small of her back pulled at the bow at the base of her corset. After a few moments of clumsy tugging and pulling, he managed to get the bow untied. Isabelle helped him with the next part, pulling and unlacing the garment so that it was loose enough for Simon to shimmy over her head. Her perfectly shaped breasts came bouncing into view, and he couldn't help but stare. It was the first time he had ever seen breasts.

"Touch them," she purred, grabbing his hand and placing it on her left breast. Simon had been hard before when he was biting her, but now, with his hand on her breast, he was rock solid. He squeezed, gently at first. Isabelle gasped, both at his cold hand on the sensitive skin of her nipple, and the sensation that Simon squeezing her breast gave her. His other hand grabbed her right breast, squeezing and fondling them both gently, while Isabelle moaned and grinded him on his lap. He took her left breast gently in his mouth, sucking and nibbling on her nipple. Isabelle threw her head back and moaned, whipping her hair over her shoulder and sending it down her back in black cascade.

"Take...your shirt off..." she moaned. Simon left her to balance on his lap, pulling his black t-shirt over his head. She ran her hands down his smooth chest. He wasn't muscular, but instead smooth and solid like a statue. She was almost jealous of his smooth skin. Her torso and chest were covered in scars from battle wounds and runes. Isabelle threw herself at Simon, kissing his neck, chest and shoulders. He groaned, low and deep. Her lips felt warm and soft on his cold chest.

She was finding it difficult to contain herself. She grabbed the waistband of Simon's jeans, tore the button open, and slid the zipper down. She smirked in satisfaction as she saw the bulge in his pants break free. The only thing left to hold it back was a pair of plaid boxers. She pulled his pants down as far as she could, and he kicked them off the rest of the way. He pulled her miniskirt down over her hips, and she danced out of it the rest of the way, kicking it to the floor on top of his jeans. Simon moaned deeply as his eyes fell on her red satin thong. He wanted nothing more than to rip that piece of fabric to shreds. He tore his boxers off and threw them on the floor, watching her face as she gazed upon his naked body. The hunger in her eyes was apparent when they finally met his again, and she wasted no time kicking her panties off so that she, too, was naked before him. Simon ached so badly to be inside of her. He leaned forward to gently lay Izzy down on her back.

And then he kind of just awkwardly gawked at her naked body. While he could have stared at her for eternity, he noticed she was beginning to look at him curiously.

"What is it?" Isabelle asked.

"I, uh," Simon mumbled. "What do I do now?" If he could blush, his face would be about as red as a tomato.

"Well, you could eat me out if you wanted to be a gentleman," she purred. Simon had absolutely no idea how to do that, but he figured it couldn't be that difficult. He hovered over Isabelle, and she spread her legs wide for him. He glanced quickly at her beautiful body beneath him, and leaned over to kiss her inner thighs. Her skin was warm and smooth beneath his lips. Then he dove right in, sliding his tongue gently at first, and then more rapidly between her folds. He licked, and gently sucked, around her clit, causing Isabelle to cry out and arch her back, pushing her hips upward. Simon thought he would never taste anything in the world as sweet as Isabelle's blood, but he had been sorely mistaken. When she screamed his name and her juices came rushing out into his mouth, it was quickly decided that he had never tasted anything so sweet in his entire life. He licked her clean, listening to her rapid breathing slow.

"By the Angel, Simon, for a virgin, you were excellent at that!" Isabelle exclaimed, pulling his face to hers for a deep kiss, in which she tasted herself on Simon's lips.

"So I guess -" Simon was about to say, "I guess it's time", but he was cut off by Isabelle pushing him down onto his back.

"Not quite," she said, crawling between his legs. Simon grunted, watching her smooth movements. "I'm all wet, but now it's your turn." Isabelle wasted no time taking his dick in her hand and shoving it down her throat. Simon moaned deeply, gripping the sheets beneath him in his fists.

"Iz..Izzy...oh..." He was about to moan, "Oh, God", but choked on the word. He watched as Isabelle's head bobbed up and down, moaning and bucking his hips forward. Anything that he could do to get his dick deeper into her throat.

Then, all of a sudden, she stopped.

"Wh-wha-? Izzy!"

"Now is the part where you fuck me," she said, flopping down onto her back. Simon crawled over her, and Isabelle wrapped her legs around his waist.

"Are you ready?" he asked, smiling tenderly at her. Isabelle was such a vixen, and as much as he enjoyed it, he wanted to make sure she knew he was doing this because he loved her, too.

"Ready."

She smiled gently back at him. Simon lined himself up at her entrance. If he were still human, he would have taken a deep breath before he slid himself inside of her, slowly. Izzy threw her head back and moaned shrilly, so much so that it was actually on the verge of a scream. Simon's eyes went wide, and he stopped.

"Izzy?" he asked, frantic with concerned. "Did I hurt you? Are you alright?"

"It's good Simon," she breathed. "It feels good."

So he went on, thrusting into her. The warmth of her body wrapped around his cold skin felt amazing. He went faster and deeper with each thrust, moaning and grunting into her ear.

"Izzy..." he grunted softly. "Izzy, I'm gonna cum...any second..." Isabelle arched her back for him as he buried himself as far inside of her as he could go. He moaned loudly and gripped the sheets, his fangs shooting out as a reaction to this fit of ecstasy. He just hovered over her for a moment or two, listening to the sound of her breathing and the racing of her heart. He slid out of her, flopping down beside her and wrapping her slim waist in his arms in one swift motion.

"You're so beautiful..." he mumbled sleepily, running his fingers through her long hair. "I'm so lucky. I love you so much."

"I love you, too," she whispered, sighing and allowing her muscles to relax as Simon traced lazy circles on her hipbone with his fingers. Simon's eyes fluttered shut, and he was just about to fall asleep when he felt her prod his side.

"Simon..." she purred.

"Isabelle?" he mumbled, half asleep. She quickly rolled him onto his back and straddled his hips, causing his eyes to shoot open.

"Let's do it again!"

"ISABELLE!"