Mammary intercourse is known as titty-fucking, titfuck, hot gay sex 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. Being forced to wear diapers as a form of humiliation is sometimes a behavior encountered in sexual masochism. Pornographic films are typically categorized as either softcore or hardcore pornography. His most famous model was Bettie Page, who became the first celebrity of bondage film and photography. No causal relationship is known between masturbation and any form of mental or physical disorder. Buttocks are sometimes emphasized in pornography, where they are often referred to as booty. 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. Studies among BDSM practitioners in the US have shown that about half of all men find the idea of bondage to be erotic; many women do as well. Mammary intercourse has sometimes been considered a hentai videos perversion. Such works have also often been subject to censorship and other legal restraints horny milfs to publication, display or possession. Cum shots typically do not appear in girl-girl scenes and orgasm is normally implied by utterances, cinematic conventions, or body movement. In humans, females generally have more round and voluptuous buttocks, caused by estrogen that encourages the body to store fat in the buttocks, hips, and thighs. Bukkake pornography involves a performer, usually female, onto whom several men or women ejaculate, usually on the face. 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. Swinging can take place in various contexts, ranging from a spontaneous sexual activity at an informal social gathering of friends to a regular social gathering in a sex club or residence.