Especially popular in post-World War 2 Japanese culture. Though the term anal sex most commonly means penile-anal penetration, sources sometimes use the term anal intercourse to refer exclusively to penile-anal penetration, and anal sex to refer to any form of anal sexual activity, especially between pairings as opposed to anal masturbation. Given the wide range of practices, some of which may be engaged in by people who do not consider themselves as practicing BDSM, inclusion in the BDSM community or subculture is usually dependent on self-identification and shared experience. Men and women may masturbate until they are close to orgasm, stop for a while to reduce excitement, and then resume masturbating. In September 2003 the BBC reported on the new dogging craze. In general, softcore pornography is pornography that does not depict explicit sexual activity, sexual penetration anime hentai or extreme fetishism. Saliva pornography involves salivation and saliva. Twink pornography features younger performers, and usually features young men under 30 who identify as gay or bisexual. A pearl necklace is a slang term referring to a sexual act in which a man ejaculates semen on or near the neck, chest, or breast of another person. Pornographic films are generally classified into sub-genres which describe the sexual fantasy which the film and actors attempt to create. With second wave feminism and growth of scholarship in women history and sexuality in the 20th century, the definition of lesbian broadened, sparking a debate about sexual desire as the major component to define what a lesbian is. Interracial pornography typically employs ethnic and racial stereotypes in its depiction of performers and many of interracial nude milfs pornographic films still include racial stereotypes, although the segregation of actors by race has diminished considerably. However, the tradition of bondage magazines continues in the form of art books of bondage photographs, gaysex published by mainstream publishers such as Taschen.