However the genre remains a very small proportion of the pornographic DVD market; for example at porn retailer HotMovies. Unlike erotic films, pornographic films contain explicit sexuality and do not claim any artistic merit. Pornography is generally classified as either softcore or hardcore pornography. In the 1970s, the hardcore pornography genre introduced the stereotypical cumshot scene as a central element of the hardcore film, in which the male actor ejaculates in a way ensuring maximum visibility of the act itself. Gang bang pornography is a type of pornography that depicts an individual engaging in physical sexual activity with multiple partners sequentially or at once. Some couples use pornography at times for variety and to create a sexual interest or as part of foreplay. Transsexual porn star Wendy Williams has stated that transsexual porn is classified as Straight Specialty. When sexual activity is centered on one of the threesome, hentai movies then the activity may be described as a gang bang of the person. Bukkake, Gokkun, Omorashi, and tentacle erotica are few uniquely Japanese genres known to western viewers. The first film was released in 1980 starring Kay Parker. Kinbaku is a Japanese gay twink porn style of bondage or BDSM which involves tying up the bottom using simple yet visually intricate patterns, usually with several pieces of thin rope . Through the 1990s, mainstream movie and television actors have been more willing to portray homosexuality, as the threat of any backlash against their careers has lessened and society acceptance of gay and lesbian people has increased. Especially popular in post-World War 2 Japanese culture. Transsexual pornography features transwomen performers, who typically have male genitalia and augmented female breasts . He talked to them extensively on camera so that both he and the viewer can come to know them before any sex scenes. Sometimes, asymmetric and often intentionally uncomfortable positions are employed to heighten the psychological impact nude milfs of the bondage.