Bear features a combination of middle-aged, hairy or overweight males. As well as traditional attraction, the topic also incorporates feederism and gaining, where sexual gratification is obtained via the process of gaining body fat. The initialism BDSM includes psychological and physiological facets: Bondage & Discipline Dominance & Submission Sadism & Masochism Types of Play This model for differentiating among these three aspects of BDSM is increasingly used in literature today. 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 gay cock pool had tried coprophilia, showing no statistically significant difference between heterosexuals and homosexuals. This technique is also used by some men who are circumcised who have excess skin left from circumcision. Mammary intercourse has sometimes been considered a perversion. A related term used in the genre is the term cougar, which implies an older woman as predator. Internationally, hentai is a catch-all term to describe a genre of anime and manga pornography. Arcane or occult pornography involves sexualized situations with an occult or magical tone or performers who costume themselves in keeping with the theme, for example, a male performer dressed as a wizard. Point hentai sex of view momporn pornography is adult entertainment filmed to look as if the watcher were experiencing the sex act themselves. Production of such films was profitable, and a number of producers specialised in their production. In Japan, point of view pornography is referred to as hamedori . A 2009 study found that heterosexual male fat admirers preferred females that were clinically overweight and rated both overweight and obese women more positively than slighter individuals. In POV porn, the shooting style is generally similar to gonzo pornography, with the person receiving sexual gratification holding the camera him or herself—aiming it down at the actress or actor who is performing the sex act.