Cock stuffing, also known as urethral sounding, involves the insertion of smooth, slender rods called "sounds" into the male urethra. This practice is often associated with the S&M community and aims to enhance sexual pleasure through urethral stimulation. Commonly used sounds include the Van Buren, which has a J-shaped bend at the end, and the Dittle, which is straight. It's crucial to use proper, sterilized equipment and ample lubrication to ensure safety and prevent injury during this activity.