The term "sex-mod" can be broken down into two words: "sex" and "mod". In the context of adult content, "sex" is quite clear. However, the word "mod" may require a little explanation. In this case, it likely refers to a modifier or variation on something.
So, "sex-mod" could be interpreted as a description for pornographic content that involves some form of variation in sexual activity. This might include roleplaying, BDSM, fetish elements, or other forms of alternative sexual expression beyond the typical vanilla sex scenarios. Remember, this term is not specifically English and may have regional variations in meaning or usage.