Although pornography has usually focused on heterosexuality, due to the prevalence of the heterosexual orientation, explicit gay material has a long history as well, which reaches back to Greek antiquity, if not to prehistory. Since at least 1973, it has also been used to refer to a sexually attractive young woman. The genres of pornography are based on the type of activity featured and the category of participants, for example mateur pornography hentai movies is a category of pornography that features models, actors or non-professionals performing without pay, or actors for whom this material is their only paid modeling work. The prostate gland is one of the organs that contributes fluid to semen. Babysitter pornography features usually teenage girls being exploited and big tit milf having taboo sex with older, male employers. Shemale is a term primarily used in sex work to describe a trans woman with male genitalia combined with female secondary sex characteristics, usually including augmented female breasts, from breast augmentation and/or use of hormones. Can also include auto-fellatio, or performing oral sex on oneself. The range of its individual characteristics is thereby wide. Enema pornography involves adults given enemas to others, often fake. Guro or Gore is a genre of Japanese pornography involving blood, gore, disfiguration, violence, mutilation, urine, enemas, or feces. See Gay-for-pay. Matsuo used amateur actresses in his videos, and he usually traveled to their hometowns for the filming. BDSM actions can often take place during a specific period of time agreed to by both parties, referred to as play, a scene or a session. However, the tradition of bondage magazines continues in the form of art books of bondage photographs, published by mainstream publishers such as Taschen. Within a BDSM or D/s context, facesitting can be an especially intense form of erotic humiliation. Pegging is a sexual practice in which a woman performs anal sex on a man by penetrating the gay movies man anus with a strap-on dildo.