Hey everybody, here is a more fluffy lemon for you guys though it does feature some taboo, as in it's kind of incest but not really as they aren't fully related! Here's Izzy/Jace, I will hopefully do a malec for you guys later.

"Are you sure you want to do this?" Jace asked Isabelle gently, sure that it was the first time he had ever spoken to a girl with concern in his bed, usually for him he just fucked people and got it over with, but he supposed Izzy was different, she was practically his little sister. Maybe that's why he was asking her, he realised, because even though he wanted to have sex with her he knew it was wrong because she was his little sister, for crying out loud.

Isabelle nodded, her eyes wide as she met Jace's stare, he was hovering just over her, shirtless. Both Jace and Alec knew that despite all of Isabelle's boyfriends and bragging about how far she would go with guys, she was still a virgin. That made Jace feel a little better though, at least he did love Izzy even if he wouldn't admit it, at least Izzy was losing her virginity to somebody who cared for her, Jace's first time had just been a one night stand.

"If I didn't want to, I would have kicked you in the balls and left you here," Isabelle said with a soft voice, "Come on, Jace. Alec will be home soon."

"So? He can't tell us what to do."

"I have a feeling he won't react too well to knowing his siblings are fucking, Jace."

Shrugging, Jace acknowledged that she was probably right. "Are you sure? If you don't want to tonight then I understand-"

"Jace, I may be a virgin but I want to do this. Please." Izzy persisted, and Jace nodded. He couldn't help himself either, she was so beautiful, he felt so proud to practically be her big brother. Her skin was creamy and exposed beneath a silky ivory slip, her black hair flowed across the hot pink sequinned cushions of her bed. She was looking up at him with keen and wide eyes, her lips were pouted…

Jace tilted his face down, placing a light kiss on her plumped lips, and then he went in again only the second time with much more feeling, his tongue entered his little sister's mouth and did a dance with her tongue, and Isabelle held one hand in his hair and the other one on his hip, feeling the toned muscles of his stomach as she moved her hand across. Then, Jace placed kissing on her jaw bone, and then down her neck, suckling on the skin their gently so he would leave light marks. His hand reached for her slip dress and he pulled the fabric down slightly, exposing her braless breasts. Her nipples were pointed, and Jace kissed the mounds on her chest and then sucked gently on the nipple, biting a little but not so it was painful, he smiled as he heard Izzy's pleasurable moan.

"Is this okay?" Jace mumbled against her skin, and she just nodded, moaning, "Jace, I need you."

Obliging, Jace pulled her silky slip up, revealing her light pink boyshort pants. As he pulled them down her legs he continued kissing down to her navel, and then he teased at her entrance, his tongue almost entering but then sliding back out, getting a taste at her soaking wetness.

"Jace…" she whined, wriggling.

Jace smiled, "Sorry, Iz."

Deciding she was wet enough to start immediately, Jace quickly pulled of his training pants, he still hadn't changed out of them after their morning lesson. He reached for a small bottle of lube and poured some onto his hand, massaging it onto his cock so he could enter Isabelle with as little discomfort for her as possible.

"Last chance to back out, Isabelle." He murmured, hovering back over her.

"I don't want to back out." She breathed, "I - I need you now."

Jace placed one last kiss on her lips, and then he entered her so slowly and gently, because even though she was strong she was still delicate, and Jace really did love her, his sister but they weren't really blood related so it was okay…

She did whimper a little, but once Jace had slowly begun to pull out and then re-enter her he could tell she was beginning to enjoy it, her whimpers became more like moans, and when he was beginning to speed up she actually arched her back in pleasure. "Oh, crap Jace you're so good at this."

When Jace eventually came, he collapsed down beside her on the bed, placing an arm loosely over her waist, spooning her body with his.

"Are you okay?"

She nodded, "I'll probably ache tomorrow." She giggled, "But that's nothing a strength rebuilding rune won't fix."

"I love you, Izzy." Jace said lowly, surprising both of them, but he was glad to have said it.

After a moments hesitation, Isabelle turned around and nuzzled her head into his chest. "And I love you."