Hey! So I know I've been very inactive on here lately but I did some writing today and thought I would share. This is Isabelle and Jace so sort of incest except not as they aren't properly related. Hope it's okay c: xx

Isabelle painted her lips red, her eyes meeting Jace's in the reflection of the mirror. He whimpered pathetically, his arms strained as he struggled against the binds tying his wrists to the bedpost. She tutted, pouting her perfect lips as she did so, "Now Jace, I told you to stay quiet and sit still." She murmured, getting up from the stool that sat in front of her dresser. She began to untie her black silk dressing gown, doing it slowly, letting the fabric whisper against her skin like a caress, knowing it would drive Jace crazy. The corners of her lips flicked upward, and she shook her black tousled waves over one shoulder.

"Are you going crazy, Jace?" She purred, and she started walking across the room towards the bed. "You know, I don't like it when you tease me. You and I both know I am the better fighter, yet you still insist on telling everyone it's you."

Glowering at her, Jace once again tugged against the binds. "Izzy stop being ridiculous." He snapped.

"Oh, he speaks." Chuckled Isabelle, sounding amused. "I was wondering why you were being so shy."

Teasingly, she lowered herself onto the bed, the tips of her fingers brushing against Jace's leg. Then moving her fingers like feet up her body, she went to the buttons of his shirt. Her face was hovering right by his and she could hear his quickening breaths. "I make you nervous, Jace." She told him like it was obvious, she made everyone nervous. "Even more nervous than everyone else because you know how dangerous it is, how dangerous it is for you to be turned on by seeing your sister in her underwear."

"I'm not turned on." Jace practically growled, "Stop being so childish Isabelle and let me go. I could easily break these binds."

Shaking her head, Isabelle smirked. "You've been trying, but you haven't been able to. I tie a good knot, Jace, and these have runes on them to make them breakable only by me."

Moving her lips closer to his neck, Isabelle began to unbutton his shirt, all the while she whispered against his skin. "I see the way you watch me in training, Jace. You don't only admire my skill, but it turns you on when I'm wearing skin tight gear. And you think it's sexy to see me kill the demons, you think it's hot when I draw them in by practically committing to fuck them and then I kill them instead."

"Isabelle, stop." Jace commanded, but again Isabelle just laughed.

"Even you, Jace Wayland, even you can't help but be enchanted by me." His shirt was fully unbuttoned now and it fell open to reveal his perfectly toned upper body, and Isabelle traced her finger up the plane going from his navel to his chest. "When you were in the infirmary and I was tending to your wounds, you fell asleep. Even whilst sleeping you looked tortured but then…"

She felt Jace tense beneath her fingers, he knew what dream she was referring to. "You were dreaming, weren't you Jace? You started moaning, you were moaning my name. I could see your cock through the sheets, and I can see it now. Your cock always gets excited when it's me." Her hands continued to wander across his body, but then they trailed down to the belt of his jeans. "But even if you find me sexy as hell, you could never fuck me because you would always be thinking about how you had sex with your sister."

"Stop it."

The belt was coming through the loops now, she was taking it off and now her hands were going to the waistline, pulling his jeans down. "So I'm going to punish you for being so rude about my fighting skills, but it's the best kind of punishment. It will be a pleasure for us both but you will always hate to love it, your own desires will make you and anyone who finds out sick to the stomach." The jeans were almost to his ankles now, Jace was just wearing his pants and his hands were bound to the bedframe, Isabelle had him right where she wanted him.

"Isabelle, this is wrong."

"Exactly." She teased, massaging her fingers up and down his inner thighs, getting dangerously close to his cock. "You know me, Jace. I always want the forbidden fruit, whatever annoys my mom and dad I'm game for. Knowing that their son and their daughter are fucking one another, that's going to drive them crazy."

"Isabelle, we can't."

"You've stopped telling me to stop now." Izzy continued, taunting him, watching as his erection pressed even harder through his boxers. "You'll tell me it's wrong but not to stop, because now you want it more than ever."

Now it seemed like Jace was even unable to speak, as Isabelle started to pull his boxer briefs down he turned bright red, pressing his lips tight together, his breaths growing even quicker as his cock grew even harder. "Do you still think I'm a bad fighter?" Crooned Isabelle, her eyes widening as his dick sprung free.

She began placing feather light kisses at the head of his shaft but each one was too quick, it was definitely torturous for Jace. "Definitely not." Jace gasped, turning redder.

"Do you still think you can insult me and get away with it? Do you, Jace?"

"No." He choked out, and Isabelle smiled at him lovingly. "Oh brother, you look so hot lying there. Do you want your sister to make you feel better?"

Looking terrified, Jace nodded.

"Say it, Jace,"

"Make me feel better."

"Call me your sister, Jace. Your sister."

Shaking his head, Jace looked like he was about to burst. "Izzy-"

"I could leave you here for Alec to find when he gets home if you want."

"Fine!" Jace cried as she was about to get up, "Please make me feel better, my darling sister."

He tried and failed to add as much snarkiness and arrogance to the last words, he ended up just sounding desperate.

Isabelle smiled, pleased, and leant back down over him. She continued kissing up and down his cock for a while but eventually she parted her lips and lowered her mouth over his cock, and she started slowly at first, the whole time her eyes on his.

"Oh, my sister, you're… you're so good at this." Jace moaned, Isabelle didn't even smile that time. She just made sensual noises as she sucked her brother's cock gradually faster, doing it on purpose as a way to torture her brother. Hearing his sister moan like that because of him should have made him disgusted but it just made him need to come.

However when he said he had to, Isabelle immediately took her mouth from his dick. She got to her feet and walked over to her drawers.

"Iz!" Jace whimpered.

Winking at the reflection in the mirror, Isabelle opened one and took out something… a cock ring. "Remember, this is a punishment." She said in a voice that suggested she was talking to a baby, and then she quickly placed the ring around his ready to burst dick. "You won't come until I say so. Maybe Alec and I will share you later."

"Isabelle, no!"

"Shh." Isabelle said angrily, and then turned back to the mirror. "Jace, your dick ruined my lipstick."

She reapplied the red paint and left Jace there, and he was unable to keep from moaning and whimpering so loudly she could hear it from down the haul.