Medical pornography involves sexualized medical, often fake, including gynecological pelvic examinations, rectal examinations, and pelvic or gynecological ultrasounds. Group sex pornography features at least two men and two women , usually more, who all perform sex acts on each other. The term comes from the French voyeur, one who looks. Pornographic films are typically categorized as either softcore or hardcore pornography. Since mammary intercourse is a non-penetrative sex act, the risk of passing a sexually transmitted infection that requires direct contact between the mucous membranes and pre-ejaculate or semen is greatly reduced. This is commonly called double vaginal penetration or double stuffing. No causal relationship is nude milfs known between masturbation and any form of mental or physical disorder. By comparison, gonzo pornography puts the camera right into the action, often with one or more of the participants both filming and performing sexual acts, without the usual separation between camera and performers seen hot gay sex in conventional porn and cinema. Rimjob pornography centers around anilingus. In humans, females generally have more round hentai sex and voluptuous buttocks, caused by estrogen that encourages the body to store fat in the buttocks, hips, and thighs. Lying face down on a comfortable surface such as a mattress or pillow, the penis can be rubbed against it. The two sets of people involved often meet either randomly or arrange to meet up beforehand over the Internet. If one person is penetrated by two objects, it is generically called double penetration . 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. Lolita pornography caters to ephebophiles.