The term "mary-green" appears to be a combination of two elements: "Mary," which is a female name often used in English-speaking countries, and "green," which can refer to the color green or a young, inexperienced person. However, without additional context, it's difficult to pinpoint the exact meaning of this specific tag. It could be referring to a scene featuring someone named Mary who is new to sex or perhaps a scene involving someone with green-colored hair or clothing. As this term seems to be a unique creation, the intended meaning might not align directly with standard English definitions.