"Dirty-Pool" in the context of a porn video tag refers to unscrupulous or dishonest behavior, often in a sexual context. This could involve manipulation, deceit, or taking advantage of someone's vulnerability for one's own pleasure. The term is derived from the concept of "pool," which typically refers to sexual activity, and "dirty" being an adjective that implies something illicit or disreputable. In essence, this tag represents a scenario where someone engages in secretive or dishonest actions to get what they want sexually.