Hentai is often associated with lewdness and inappropriateness, but is actually a legitimate part of manga and anime. It is a genre of pornography that has been around for over 800 years. It uses exaggerated body parts and internal cavities to depict sexual acts that are physically impossible. The popularity of hentai began after World War II, and is now widespread. It can be found in a variety of media, such as books, video games, manga, and anime. It can include heterosexual and homosexual interactions.