In the dim light, the siblings sit, backs against opposite walls, socks still on. She slides her hand into her shorts, rubbing her pussy through her panties. He follows suit, pulling out his cock, stroking it gently. Their eyes meet, filled with lust and guilt. She licks her fingers, wetting them, then plunges them back into her pussy, fucking herself while he jerks off faster. Their breathing grows ragged, bodies tense, until they both climax silently, socks soaked with their forbidden lust.