The porn video tag "gillinter" appears to be a combination of two words - "gill" and "inter." However, it does not seem to have a direct meaning in English. It could be an attempt at creating a new term for a specific sexual act or fetish related to gills or intercourse.
In the context of porn video tags, creators often use their own unique terms or abbreviations that may not necessarily have standard definitions. These terms are usually intended to convey particular actions, positions, or preferences within a given adult content. To understand the meaning behind "gillinter," one would need more information or context.