The provided tag "du" is not a clear porn video tag. However, it could potentially mean "double penetration." Double penetration is a term often used to describe a specific sexual act in porn videos where two men penetrate one woman or a man and a woman simultaneously. This usually involves either two men penetrating a woman vaginally and anally at the same time, or a woman performing oral sex on one man while allowing another to penetrate her vaginally or anally.