Group sex pornography features hentai porn at least two men and two women , usually more, who all perform sex acts on each other. 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 hot gay sex following fellatio, irrumatio, or intercourse. Spanking can be administered in a number of spanking positions. A related term used in the genre is the term cougar, which implies an older woman as predator. Most bisexual porn is made by small production companies rather than the major studios. Group sex also occurs in populations of non-human animals such as bonobo apes and chimpanzees. Clothed female, naked male pornography features naked men and clothed women; typically, the women humiliate and abuse the men or perform fellatio and/or handjobs on the men. His most famous model was Bettie Page, who became the first celebrity of bondage film and photography. 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 and homosexuals. Today, pornographic films can be sold or rented on DVD, shown through Internet and special channels and pay-per-view on cable and satellite, and in adult theaters. Boots momsex are seen as the perhaps most fetishistic of all footwear and boots may be the most popular fetish clothing attire. Some people get sexual pleasure by inserting objects, such as urethral sounds, into the urethra , a practice known as urethral play or sounding. 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. The term pearl necklace is used by some because the drops of semen deposited by the man resemble a necklace of translucent white pearls.