This porn video tag refers to a specific category within the adult content industry. The term "old man" suggests that the actors involved in the scene are mature, possibly older individuals. The word "gay" indicates that the content of the video is focused on same-sex male relationships and sexual acts. In this context, it can be understood as "a scene involving an older man engaging in homosexual activities with another man." This tag serves as a label to help users find specific content they are interested in within the vast pornographic landscape.