M-kun and Ayumi, forbidden lovers bound by blood and societal norms, find themselves alone in the dimly lit attic. Ayumi, her body flushed with heat and desire, can't help but notice the bulge in M-kun's pants. She tentatively reaches out, her small hand wrapping around his cock through his jeans. M-kun sucks in a breath, his eyes meeting hers, filled with a mix of fear and lust. "We can't," he whispers, but his body betrays him as he hardens in her hand. Ayumi, emboldened, unzips his jeans and pulls out his cock, licking her lips as she prepares to taste her brother.