DMD stands for Double-Penetration Male Dominant. In a porn video, it refers to a scene where two men penetrate the same male partner simultaneously, with one person taking a dominant role and controlling the actions of both participants. This is often associated with BDSM or power play dynamics, as the submissive person may be restrained, gagged, or otherwise bound and unable to resist the penetration. DMD scenes can involve anal, oral, or fisting penetrations and are popular in gay pornography.