Real school shots or videos which are sexualized may violate privacy laws in some countries. Clothed male, naked female is one-sided female nudity in which one or more females are nude hentai sex while one or more men are clothed. Hentai narrow Japanese usage and broad international usage are often incompatible. Pornography may fall into more than one genre. Lying face down on a comfortable surface such as a mattress or pillow, the penis can be rubbed against it. Interactive pornography, available in CD-ROM and DVD format, allows the viewer to select the particular acts performed at any one time, sometimes with the camera providing a first person view. The consensual submission of the submissive is sometimes demonstrated to others by symbols indicating his/her belonging to the dominant, such as wearing a collar, special tattoos, piercings, a very short haircut or a bald head. A bisexual threesome may involve a man having sex with a man and a woman, the woman having sex with a man and a woman, or all three having sex with each other. It is geared towards heterosexual men, who most typically define momporn a threesome as such. These are often fake. Perhaps following the example set by gay pornography, they have become a popular subgenre within heterosexual pornography since the turn of the century, featuring both vaginal and anal ejaculations. Mammary intercourse is known as titty-fucking, titfuck, gay fuck or a titjob in the United States, as well as tit wank or French fuck in the United Kingdom - the latter term dating back to the 1930s; while a more jocular equivalent is a trip down mammary lane. Bondage pornography specializes in the depiction of sexual bondage or BDSM activities as photographs, stories, movies, or drawings. What seems clear from the historical record is that much of the lesbian material in pornographic texts was intended for a male readership. Spanking can be administered in a number of spanking positions. Content featuring male bisexuality has been a growing trend since the advent of internet pornography.