Also known as: ディフェンスに定評のある湯気, 湯気ブラ, 鉄壁の湯気
A classic way to conveniently censor naughty parts of characters is to have large amounts of Steam obscure the right places. This is assumed to be better than using bar or Mosaic Censoring because it feels more natural and does not disturb the scene as much.
Closely related is the Soap Censor.