The Dirtiest Thing I Have Ever Done Ch2

A continuation picking up exactly where the last chapter ended

He reached down, his fingers finding the hem of the yellow sundress. The fabric felt soft, almost delicate, between his fingertips. He could feel the warmth of her skin beneath.
“This dress looks a little constricting, and Emma is watching this interaction through the crack of her door as she rubbing her pussy,” he murmured, his voice a low growl against her ear, the words a delicious secret shared only between them. He felt a shiver run through her, a tremor that echoed the rising heat in his own body. He tugged at the hem, slowly, deliberately, pulling the soft yellow fabric up her thighs, revealing more and more of the cotton panties stretched tight across her mound.
“She’s watching?” Lizzie’s voice was a breathless whisper, a mix of shock and a thrill that vibrated through her. Her eyes, wide and dark, flickered towards the closed door, then back to his, a daring spark igniting within their depths. “Big brother, are you sure?”
“Absolutely certain,” he confirmed, his gaze unwavering, fixed on the soft swell of her inner thigh as he continued to inch the dress higher. The fabric bunched around her waist, revealing the entirety of the white cotton panties, now damp with her arousal, clinging to the dark shadow between her legs. He could see the faint outline of her labia beneath the thin cotton, a tantalizing promise. “She’s a very curious little sister, isn’t she?”
“Oh, Kai,” she breathed, her hips arching slightly, pressing against his hand as he continued his slow ascent. Her fingers, still clutching the fluffy comforter, tightened, knuckles white. “This is… this is insane.” But her eyes, full of a dangerous hunger, told a different story. The blush on her cheeks deepened, spreading down her neck and across her chest, highlighting the erect peaks of her nipples that strained against the air.
He leaned in, his lips brushing the sensitive skin just below her ear, sending another shiver through her. “Insanely good, little sister. Isn’t that what you mean?” His hand moved from the hem of the dress, sliding beneath the bunched fabric, his palm flat against the soft curve of her buttock, squeezing gently. The cotton panties, already damp, became slicker under his touch.
“Yes,” she moaned, the word barely audible, a fragile sound of surrender. Her head tilted back, exposing the delicate line of her throat, an unspoken invitation. “Insanely good, big brother.” Her legs parted slightly, an unconscious movement, granting him more access.
He savored the moment, the exquisite tension building between them, the knowledge of Emma watching adding a layer of forbidden spice to the air. He slipped his fingers under the elastic of the panties, his thumb brushing against the damp cotton, feeling the heat radiating from her. “Big brother wants to make sure his little sister is completely comfortable, completely free.” With a swift, practiced motion, he hooked his fingers under the waistband and pulled, stripping the small cotton panties down her legs. They slid over her knees, then her calves, finally pooling around her ankles. He kicked them away, sending the innocent white panties across the room