As the ground beneath them convulses, a brother and sister huddle close, their terrified hearts pounding in sync. The sister's breath hitches as she notices her brother's growing erection, straining against his pants. She licks her lips, her eyes meeting his, and they share a silent understanding. He slips a hand under her shirt, cupping her breast, his thumb brushing against her hardening nipple. She gasps, arching into his touch, as he slides his other hand down her pants, finding her wet, eager pussy. They fuck hard and fast, their bodies slapping together, their cries of pleasure drowned out by the rumbling earthquake.