This is also the gay bear porn case in many relationships not considering themselves as sadomasochistic; it is considered to be a part of BDSM if it is practiced purposefully. The sub-genres usually conform to certain conventions, and each may appeal to a particular audience. Enema pornography involves adults given enemas to others, often fake. Social attitudes towards the discussion and presentation of sexuality has become more tolerant and legal definitions of obscenity lesbian hentai have become more limited, leading to an industry for the production and consumption of pornography in the latter half of the 20th century. Accepting that Eros is not always pretty, and may involve the forbidden or taboo - as with women pornography – forms part of the struggle with the good girl/bad girl or virgin-whore split in postmodern femininity. Kinbaku is a Japanese style of bondage or BDSM which involves tying up the bottom using simple yet visually intricate patterns, usually with several pieces of thin rope . As with most forms of sexual activity, anal sex participants risk contracting sexually transmitted infections . The higher pay scale and profile within a production often leads to group scenes where a straight actor only tops. Bukkake, Gokkun, Omorashi, and tentacle erotica are few uniquely Japanese genres known to western viewers. The fetish centers nude milfs around this fantasy portrayal. Interracial pornography typically employs ethnic and racial stereotypes in its depiction of performers and many of interracial pornographic films still include racial stereotypes, although the segregation of actors by race has diminished considerably. Facesitting is common among dominant and submissive individuals, for demonstrating superiority and for sexual gratification. Anti-pornography psychologist Ana Bridges and colleagues conducted a content analysis of best-selling heterosexual pornographic videos showing that over 96% of all scenes concluded with a male performer ejaculating onto the body of his female partner.