Wirtualna wycieczka po Lying face down on a comfortable surface such as a mattress or pillow, the penis can be rubbed against it. In the 18th and 19th centuries, some European theologians and physicians described it as heinous, deplorable, and hideous, but during the 20th century, these taboos generally declined. The porn industry and viewing public were shocked by the then-taboo spectacle of a white woman having sex with a black man. Fisher said that perhaps, the fleshy, rounded buttocks attracted males during rear-entry intercourse. Use of the agreed safeword milf fucking is seen by some as an explicit withdrawal of consent. It is also followed by dedicated industry publications and trade groups as well as the mainstream press, private organizations , government agencies, and political organizations. The industry generally refers to such films as adult films, which is part of adult entertainment. Particular areas and processes of the body that change during pregnancy may also become the focus of psychological investment, but nudity or sexual activity is not always essential, and in some cases actual pregnancy is not necessary to invoke arousal. It is also known colloquially as gushing or squirting, although these are considered to be different phenomena in some research publications. Group sex most commonly takes place in a private sex party or semi-public swinger gathering, but may also take place at massage parlors or brothels or, in some jurisdictions, at purpose-built locations such as sex clubs. The first explicit pegging scene is believed to have been in the 1975 pornographic film The Opening of Misty Beethoven. Two women tapegagged and cuffed to iron bars Bondage and Discipline are two aspects of BDSM that do not seem to relate to each other because of the type of activities involved, but they have conceptual similarities, and that is why they appear jointly. Patricia Hill Collins, an African-American writer, theorizes that this is derived from a stereotype that those of black descent are promiscuous, and their buttocks are objectified by porn as a result.