"Gemanzo" is not a common porn video tag, and it seems to be a mix of two words: "german" and "manzo". Based on this assumption, the meaning might be related to German men or possibly referring to German-speaking countries. However, without more context or information, it's difficult to determine an exact meaning for this term as it relates to adult content. It is possible that it could refer to a specific type of sexual act performed by German individuals or individuals speaking German, but without further clarification, it cannot be specified accurately.