The porn video tag "zombie-retreat" seems to describe a scene or theme that involves zombies retreating, possibly implying a scenario where the individuals involved are engaged in sexual activities with zombies who are then forced to retreat for some reason. This could involve a situation where the protagonists successfully manage to repel or overpower the zombies, making them withdraw or flee. Note that the interpretation of this tag is based on common adult video themes and may not be an exact representation of the intended meaning in your specific context. Always consider the overall content and context when using such tags.