A/N: This chapter contains pure, sexy blackcest (yes, adult content and big kid words). Please don't read if: a) the pairing, or b) sex, offends you. No flames please

Chapter 4

Narcissa shivered, though she was more than toasty. Her sister's body heat melted her skin and made her tingle. Bella's lips were deliciously soft; her hair tickled Narcissa's bare collarbone. This was not the first time her sister had kissed her.

"Bella," Narcissa pushed her away gently. "Stop."

"What's wrong, Cissy?" Bella pouted, a look that was oddly attractive on her small face and full lips. "Do you think Lily'll be jealous?"

She whispered as she leaned in to kiss her sister again. Narcissa felt Bella's long nails digging into her wrists. She was pinned. She moved her head to the side, but Bella only took the opportunity to place warm, sodden kisses along her jawbone and neck.

"I just wanted--" Bella said between kisses, "to show you how fantastic it'll be with her."

Narcissa helplessly sighed, simultaneously uncomfortable and tingling. Bella released Narcissa's arms to begin unbuttoning her shirt.

"Bella, no!" Narcissa said quietly.

"Cissy! We're sisters. I've seen it all before," Bella cooed as she finished the last button. She opened Cissy's shirt slowly, the corners of her mind curling into a smile. "Though you were much younger then…"

Narcissa tried to reach to close her shirt, but Bella swung her leg over, sitting atop Narcissa, and pinned her arms beside her. She leaned over Narcissa and Narcissa tried to avoid the sight of Bella's open shirt in front of her. She had always admired her older sister's full bosom compared to her own, though it wasn't jealousy she was feeling as she looked at Bella's pearly white skin beneath her unbuttoned white shirt.

Bella leaned slowly forward, placing kisses along Narcissa's jawbone and down her neck. Narcissa resisted closing her eyes; every time she did she only saw Lily. She wondered if her sister had enchanted her somehow and made it impossible for the image of Lily to leave her closed eyes. But if she kept them open, she could only see her sister.

It was wrong. She knew it was wrong. Her sister should not send shivers down her arms or tingles between her legs, and yet she was lying underneath Bella as she swarmed Narcissa's body with tepid, practiced kisses. She found herself sighing as Bella's hands moved slowly to her breasts. Her eyes closed of their own accord, and Lily's bright, smiling face and fluttering red hair stared back at her. Quickly, Narcissa opened her eyes, unable to bring herself to think of Lily as her sister was kissing her.

"Bella," she whispered, almost inaudibly.

"Mmm" Bella hummed into her skin, her teeth surely leaving marks as they nibbled their way down her chest. "Yes, it's me Cissy. It's always been me you've wanted. I'm here now."

Bella's whispers only made Narcissa tremble more. Her soft breath was hot against Narcissa's bare breasts, and she almost jumped at the feeling of Bella's warm mouth enveloping each one individually. Narcissa felt her stomach tighten and the familiar tingle returned to her pelvis. She hoped Bella was only teasing her. She hoped she wouldn't go further. But as Bella's hands almost viciously pulled Narcissa's pants down, she knew she was trapped.

"Bella, please! What would mother think?" Narcissa all but screamed. Her arms were pinned again and Bella's legs held her own.

"Shh!" Bella put a finger to Narcissa's lips. "What a silly time to be thinking about mother!"

With that, she moved her hand between Narcissa's legs. She didn't tease, didn't give Narcissa time to escape. Narcissa gasped as Bella's cool fingers fondled her sensitive folds.

"Cissy," Bella smiled as she moved her lips to caress her sister's. "You're quite turned on…"

Narcissa felt herself blushing, feeling Bella's fingers in her wetness. Bella's other hand caressed her breast and her mouth moved again to Narcissa's. Narcissa was turned on, and couldn't help but kiss her sister back. Their tongues playfully flicked and Narcissa's hand moved to Bella's head, pulling her closer. Bella, encouraged and more turned on, sat up straighter and looked down at Narcissa.

"Do you want me to?" She asked deviously. Her smile abated and a look of pure hunger shone in her eyes.

"Huh?" Narcissa breathed. She didn't know what she was asking for, but Bella needed no more prompting. She slid herself down Narcissa's body, hungrily kissing at her breasts and stomach. She was now between Narcissa's legs, her hands gently spreading what was before her. Narcissa watched in disbelief and lust as Bella's mouth covered her mound. She let out a gasp, her fingernails digging into her sheets.

"Oh, Bella…" she breathed, her eyebrows creased in pleasure.

Bella's large, dark eyes looked up at Narcissa, turning her on even more. Bella's tongue swirled and sucked about Narcissa's nub, and Narcissa felt the tingle she was only used to after touching herself during showers. Her hands instinctively moved to her breasts and she arched her hips as she felt the "tingle" explode into a delicious ache that spread through her whole body until it released her, groaning, back onto the bed.

Bella gave her a few more light kisses before sitting back up. Her shirt had somehow become completely unbuttoned, and Narcissa flushed at her sister's fully naked breasts in front of her. She also noticed Bella's hand up her skirt and between her legs, stroking ferociously. A strong part of her desired to return the favour to Bella, though she mistrusted she could do it successfully.

She hardly had time to make a decision. Bella's head fell back as she whimpered lightly and squeezed her legs together in her orgasm. Narcissa watched with rosy cheeks as Bella's free hand gently caressed her breasts and she brought her head back up. Her face was softer than Narcissa had ever seen it. She almost looked sweet.

Bella flashed a smile at Narcissa before hopping off the bed, buttoning up her shirt and patting down her skirt.

"Well, I've got to be off," she said simply, walking towards the door. "Put your clothes back on, Cissy. The other girls will surely be up soon."

Narcissa, still lying half-undressed on the bed and still tingling from her high, watched her sister run her fingers through her messy black curls and exit the dormitory.

Narcissa pulled her pants back up quickly, ignoring the wetness still lingering between her legs. She then began to button her shirt, resolving she would never, no matter how good it felt, let her sister do that to her again.

Experimentally, she closed her eyes. Lily Evans was no longer there. Instead, she could only see Bella; her eyes shining brightly at her in the dark.