This porn video tag is describing a scene involving older homosexual men. The term "old" refers to the age group of the participants, which can be subjective but generally indicates more mature or seasoned individuals. In this context, it is specifically referring to an older demographic in the gay community.
The term "gay" is used to denote that the content features men engaging in sexual activities with other men, rather than women or individuals of another gender. This tag is geared towards adult viewers who are interested in this specific genre of pornography featuring older gay men.