marshmallow-the-vampire-slayer:
Buffy the Vampire Slayer - TV Tropes: Scenery Censor
Scenery Censor: A completely nude character’s “naughty bits” are blocked from the camera by a convenient prop or oddity of architecture, yet every other character in the scene gets an eyeful, usually resulting in either ogling and nosebleeds, or Squicks and grabs for the Brain Bleach. Usually this is used just out of cultural necessity, and/or to hide the fact that the cast members involved weren’t really nude in the filming of the scene.