The porn video tag "free-gay-movies" refers to a specific category of adult content. In this case, the term is made up of three parts:
1. Free - This indicates that the movies or videos being referred to are available without any cost to the viewer. These can either be completely free to access and watch or have some form of fee waived through promotions or memberships.
2. Gay - This specifies that the content is centered around homosexual male relationships, typically featuring explicit sexual acts between men.
3. Movies - This refers to the format in which this adult content is presented, as a film or movie. These can be full-length features or shorter scenes, often with a narrative or theme connecting the various scenes.
So, "free-gay-movies" refers to free gay porn movies or films available for adult audiences.