As the door clicks shut, the sisters' hearts pound in unison, echoing the throbbing between their legs. Michelle, the more adventurous of the two, tentatively reaches out, her fingers brushing against her sister's thigh, feeling the muscles tense and then relax into the touch. Their breaths sync, growing heavier as they dare to explore each other's bodies, their inhibitions melting away in the confined space, replaced by a hunger for the forbidden.