My girlfriend, always eager to experiment, takes my throbbing cock in her skilled hands, teasing and stroking it with expert precision. She lubes up a metal sound, its coldness sending shivers down my spine as she gently inserts it into my urethra. My moans fill the room as she twists and turns the sound, hitting my prostate and sending waves of pleasure coursing through me. She alternates between fucking my cock with the sound and jerking me off, pushing me closer and closer to the edge. Finally, with a loud groan, I cum hard, my load shooting out and coating her fingers and my stomach.