Other objects such as ball point pens and thermometers are sometimes used, although this practice can lead to injury and/or infection. As a form of non-penetrative sex, it can be done for its own enjoyment or as foreplay. There are gayporn various subcultures under this umbrella term and distinct difference between these subcultures. Point of view pornography is adult entertainment filmed to look as if the watcher were experiencing the sex act themselves. For some people, non-penetrative sex is the primary sexual activity of choice above all others. Participants who exert sexual control over their partners are known as dominants or tops while participants who take the passive, receiving, or obedient role are known as submissives or bottoms. Pornography may fall into more than one genre. No causal relationship is known between masturbation and any form of mental or physical disorder. Preggo pornography features pregnant performers and may include erotic lactation as a fetish. In the West, masturbation in private or with a partner is generally considered a normal and healthy part of sexual enjoyment. Sigmund Freud considered foot binding as a form of fetishism. His most famous model was Bettie Page, who became the first celebrity of bondage film and photography. Examples of mentally oriented practices are education games, during which the dominant requires certain forms of behavior from the submissive. Many transgender people regard the term shemale as offensive, arguing that it mocks or shows a lack of respect towards the gender identity and gender expression of transgender individuals; in this view, the term emphasizes the biological sex of a person and neglects their gender. New York photographer Irving Klaw also published illustrated adventure/bondage serials by fetish artists Eric Stanton, Gene Bilbrew, Adolfo Ruiz and others. Likewise, Fox Broadcasting Company has also dedicated an entire evening programming block to adult animation programs, known as Animation Domination.