They may repeat this cycle multiple times. Pornographic films or sex films are films that present sexually explicit subject matter for the purpose of sexual arousal and erotic satisfaction of the viewer. Pornographic films present sexual fantasies and usually include erotically stimulating material such as nudity. They cited the Internet and text messaging as common ways of organising meetings. Pornography is generally classified as either softcore or hardcore gay cock pornography. Mutual masturbation is a sexual act where two or more people stimulate themselves or one another sexually, usually with the hands. Individuals who can change between top/dominant and bottom/submissive roles—whether from anime hentai relationship to relationship or within a given relationship—are known as switches, though the term switch in this context is occasionally seen as derogatory and is rejected by many who might simplistically fit the definition. Others involve partners who naturally have a significant difference in size. 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. It can also be heightened by the person saying that they have to urinate. Pegging is a recently invented word which features a woman penetrating a man with a strap-on dildo. The surfacing of sex tapes has become so common that some are leaked as a marketing tool to advance or establish a media career. Masturbation has been depicted in art since prehistoric times and is mentioned and discussed in very early writings. Rape itself is a crime in many countries. In general, softcore pornography is pornography that does not depict explicit sexual activity, sexual penetration or extreme fetishism. Softcore pornography generally contains lesbian milfs nudity or partial nudity in sexually suggestive situations, but without explicit sexual activity, sexual penetration or extreme fetishism, while hardcore pornography may contain graphic sexual activity and visible penetration, including unsimulated sex scenes.