The given tag "underw" seems to be a shortened version of the term "underwear." In the context of adult videos, it may refer to scenes or content where individuals are wearing or interacting with underwear. This can include different types of undergarments such as briefs, thongs, g-strings, and other styles. These types of scenes often involve teasing, stripping, or sexual activities involving the removal or manipulation of underwear. It may also refer to certain fetishes related to undergarments, like latex or lingerie.