"TS" in the given tag stands for "Transsexual," which refers to individuals who have undergone or are in the process of transitioning from male to female. In this context, "Mistress" refers to a dominant woman, often in a BDSM or dominatrix context. So, "ts-mistress" indicates a transsexual woman taking on a dominant role in a sexual scenario, typically involving submission and control over male partners