Bestiality is illegal in many countries. Cuckolding can also be mixed with other non-monogamous relationship arrangements with which it has substantial overlap such as Swinging, wife-swapping, open relationships, and polyamory, etc. A survey by the New York City Department of Health and Mental Hygiene found that heterosexual women are more likely to bareback when engaging in anal sex than homosexual and bisexual men. Women with women Main article: Lesbianism in erotica: Lesbianism in contemporary pornography Lesbian or girl-girl pornography features women engaged in sex together, but is typically aimed at a male audience. Group sex pornography features at least two men and two women , usually more, who all perform sex acts on each other. This type of pornography is almost exclusively hentai, as true hermaphroditic humans are not fertile and are not usually found in nature. Diaper pornography involves performers wearing diapers, sometimes with an adult performer acting in the role of a caretaker. It is typically animated pornography, as the legal age to be featured in a pornographic hentai porn film in Japan is 18. Such ejaculation can be done by mammary intercourse, or masturbation over the other person, or result from the withdrawal of the penis from a partner mouth as he is ejaculating following fellatio, irrumatio, or intercourse. A pornographic work is characterized as hardcore if it has any hardcore content, no matter how small. Common mature milfs phrases used to refer to these individuals are chicks with dicks or the derogatory term shemale, although these are generally considered pejorative among transwomen. Pro-am pornography is sub-genre of amateur pornography that refers to professionally made porn that features amateur actors/actresses, often appearing for the first time in a pornographic film. A study of 164 males in Finland from two SM clubs found that 18.2% had engaged in coprophilia; 3% as a sadist, 6.1% as a masochist, and 9.1% as both. 18% of heterosexuals and 17% of homosexuals in the study pool had tried coprophilia, showing no statistically significant difference between heterosexuals gay twinks and homosexuals.