Most bisexual porn is made by small production companies rather than the major studios. Sadism describes sexual pleasure derived by inflicting pain, degradation, humiliation on another person or causing another person to suffer. Creampie, also known as internal cum shot, and, in homosexual contexts, also known as breeding and seeding, is a slang term used in pornography to describe when a male ejaculates inside his partner vagina or anus. The industry generally refers gay bear porn to such films as adult films, which is part of adult entertainment. Lesbian pornography typically features a wider range of appearances and body types than is typical of mainstream pornography. Erotic spankings are commonly combined with other forms of sexual foreplay. Snowballing or snowdropping is the human sexual practice in which one person takes someone else semen into his or her mouth and then passes it to the mouth of the other, usually through kissing. These actors often play the top roles but this is not always the case, such as with Kristen Bjorn and some Bel Ami models. This makes varying degrees of stimulation an integral part of oral sex for many men. Some pornographic films use an artificial lesbian milfs semen substitute to simulate or enhance creampie shots. Cartoon pornography is the portrayal of illustrated or animated fictional characters in erotic or sexual situations. The consensual submission of the submissive is sometimes demonstrated to others by symbols indicating his/her belonging to the dominant, such hentai videos as wearing a collar, special tattoos, piercings, a very short haircut or a bald head. 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. Sub-genres can also be classified into the characteristics of the performers or the type of sexual activity on which it concentrates, and not necessarily on the market to which each sub-genre appeals.