A common way that these are depicted in a single scene is with one woman and two men performing together. One or more of the participants may engage in autoerotic sexual activity, such as masturbation, possibly without physical contact with the other participants. Examples include the Girls Gone Wild and Girls Who Like Girls Series. The name of the practice, when it is done in a repeated in-and-out motion, is derived from its passing resemblance to the dipping of a tea bag into a cup of hot water as gay cock a method of brewing tea. Can also nude milfs include auto-fellatio, or performing oral sex on oneself. These scenes may either 3d hentai have the cameraman directly engaging in sex or merely filming others having sex. The nipples are erogenous zones, and vigorous stimulation of them during masturbation usually causes the penis to become erect more quickly than it would otherwise. Pornography is generally classified as either softcore or hardcore pornography. In the 1970s, the hardcore pornography genre introduced the stereotypical cumshot scene as a central element of the hardcore film, in which the male actor ejaculates in a way ensuring maximum visibility of the act itself. Insertion in pornography features women inserting various odd objects into their anus or vaginas. Guro or Gore is a genre of Japanese pornography involving blood, gore, disfiguration, violence, mutilation, urine, enemas, or feces. Tentacle rape or shokushu goukan is found in some horror or hentai titles, with tentacled creatures having sexual intercourse with female characters. Such explicit sexual interaction is seen only rarely in public play spaces, and it is sometimes specifically banned by the rules of a party or playspace. Some BDSM practitioners prefer a code of behavior that differs from SSC and is described as risk aware consensual kink , indicating a preference for a style in which the individual responsibility of the involved parties is emphasized more strongly, with each participant being responsible for his or her own well-being.