Unbeknownst to her brother, his sister's gaze lingers on his crotch, her mind filled with forbidden images of his cock. She imagines it, thick and veined, pressing against his jeans, begging for release. Her nipples harden, chafing against her bra, as she pictures herself on her knees, unzipping his pants, his cock springing free, ready for her hungry mouth. She licks her lips, her pussy growing wet with the taboo fantasy, her heart pounding with anticipation and shame.