A spanking may be carried out with the use of a bare or gloved hand, or with any of a variety of implements, including a paddle, strap, hairbrush, feather duster or belt. Such grounds and even the definition of pornography have differed in various historical, cultural, and national contexts. A 2009 study found that heterosexual male fat admirers preferred females that were clinically overweight and rated both overweight and obese women more positively than slighter individuals. Following World War II, during a period of social repression when governments actively persecuted homosexuals, women developed networks to socialize with and educate each other. It is also hentai videos referred to as anal–oral contact and anal–oral sex, or colloquially as rimming or a rim job, and may be performed by or on people of any sexual orientation for personal pleasure or as naked milf a form of erotic humiliation. Point of view pornography is adult entertainment filmed to look as if the watcher were experiencing the sex act themselves. In POV porn, the shooting style is generally similar to gonzo pornography, with the person receiving sexual gratification holding the camera him or herself—aiming it down at the actress or actor who is performing the sex act. Group sex also occurs in populations of non-human animals such as bonobo apes and chimpanzees. The naked appearance of actress Demi Moore in the advanced stage of pregnancy on the cover of Vanity Fair magazine in 1991 marked the beginning of a period which has since seen pregnancy presented by celebrities as a glamorous state of living, while also creating a market for photographers to produce images of pregnant mothers, and for fashion stylists to introduce pregnancy styling to their business. Testosterone discourages fat storage in these areas. Female masturbation involves the stroking or rubbing of a woman vulva, especially her clitoris, with an index or middle fingers, or both. The term breast fetishism is also used to refer to cultural attention to female breasts and the sexuality they represent, with debate continuing as to whether the modern widespread fascination with breasts among heterosexual males in western societies gaysex is a sexual fetish.