"TS" stands for "Transsexual," which refers to a person whose gender identity is different from their assigned sex and has undergone or is undergoing gender transition. In the context of porn, it typically means a performer who was assigned male at birth but now identifies and presents as a woman.
"Femdom" is short for "female dominance." This tag implies that the video involves a female-identifying character taking on a dominant role in sexual situations or BDSM play, possibly over a male or transsexual partner. The focus here is on the power dynamics and control typically associated with dominant/submissive relationships.