The given porn video tag "valeska" appears to refer to the name of a performer or adult actress. In this case, Valeska would be the name or stage name of the person involved in the sexual content of the video. It is not a specific term or action related to pornographic material.
Valeska could also potentially be a title or name of a scene/video featuring this performer. For those familiar with adult films, knowing who Valeska is might provide more context or understanding about what kind of content they produce.
Since the given tag is only one word and not a phrase or combination of words, it's hard to determine its exact meaning without further context or information.