The unknown stranger's body arches in response to their own touch, their breath hitching as they imagine the forbidden. They picture rough, calloused hands replacing their own, a hard, throbbing cock replacing their fingers. Their other hand reaches up, pinching and rolling a stiff nipple, sending jolts of pleasure straight to their core. They can feel the tension building, their body quivering as they teeter on the edge of ecstasy. With a final, deep thrust of their fingers, they tumble over into a shattering orgasm, their body convulsing as they ride out the waves of pleasure, their secret safe in the darkness.