Naked Apron

The Naked Apron (裸エプロン), is the practice of wearing a conventional apron over a nude body by women. It is a popular concept for both pornography and fanservice.

History
The practice was originally seen on erotic pin-up pictures during World War II; titillating shots of women in otherwise normal domestic situations, such as cooking or cleaning. These images, among others, were emulated by Japanese artists during the time when manga began to develop as an art form and became a part of the country's visual culture.

The design of the practice is based on the theme of domestic sexuality involving levels of modesty, seduction, and submissiveness; the idea of a woman subtly seducing her lover by surprising him that behind the apron she isn't wearing anything. The practice is frequently used in the media for erotic surprises; allowing the character to appear with modesty preserved from the front but with a risqué surprise for the viewer when they turn around.

While the practice largely entails that the practitioner is naked underneath the apron, variants can feature the practitioner wearing undergarments, lingerie or a swimsuit underneath instead.

Trivia

 * The practice is extremely popular amongst couples in Japan, as it is considered a traditional form of foreplay between newlyweds. As such, it comes up extremely often in Anime and Manga for fanservice, especially in Harem anime and Magical Girlfriend shows.
 * Some nudists do wear an apron when they are cooking but the only reason for them to do so is to protect themselves from physical injuries.