Often other friends and community members may witness the signing of such a document in a ceremony, and so parties violating their agreement can result in loss of face, respect or status with their friends in the community. Examples of mentally oriented practices are education games, during which the dominant requires certain forms of behavior from momsex the submissive. The activity is done by itself or as a part of or prelude to other activities which many times involve sex. Cartoon pornography depicts illustrated or animated fictional characters in erotic and sexual situations. Bukkake pornography involves a performer, usually female, onto gaysex whom several men or women ejaculate, usually on the face. 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. Clothed male, naked female is one-sided female nudity in which one or more females are nude while one or more men are clothed. The term BDSM dates back to 1969; however, the origin of the term BDSM is unclear and is believed to have been formed either from joining the term B&D with S&M , or hentai movies as a compound initialism from B&D, D&S , and S&M. Yaoi is anime or manga that features gay males . The term pearl necklace is used by some because the drops of semen deposited by the man resemble a necklace of translucent white pearls. At the end of the evening the female partners would randomly select keys from the bowl and leave with that key owner. Buttocks are sometimes emphasized in pornography, where they are often referred to as booty. 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. Commenting on why there are not as many female macrophiles, psychologist Helen Friedman theorized that because women in most societies already view men as dominant and powerful, there no need for them to fantasize about it.