Sadism describes sexual pleasure derived by inflicting pain, degradation, humiliation on another person or causing another person to suffer. As well as traditional attraction, the topic also incorporates gay twink porn feederism and gaining, where sexual gratification is obtained via the process of gaining body fat. A study of the condom usage habits of New Zealand sex workers said that they offered various safe sex alternatives to vaginal sex to clients who refused to wear a condom. Its gain in prominence has been attributed to its depiction hentai sex in the film Pecker, which was released in 1998. 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. The neologism pegging was popularized when it became the winning entry in a contest in Dan Savage Savage Love sex advice column, held after an observation was made that there was no common name for the act. Typically features adult, masculine men with varying degrees of muscle, body fat, and body hair, akin to beefcakes, or bears. The glans itself may widen and lengthen as the stimulation continues, becoming slightly darker in colour, while the gliding action of the foreskin reduces friction. Some are aroused from wetting their diapers, others like messing their diapers. 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. The industry generally refers to such films as adult films, which is part of adult entertainment. Special nude milfs forms include erotic roleplay like ageplay, in which a difference in age, either real or enacted, formulates the background; or petplay. In POV porn, the shooting style is generally similar to gonzo pornography, with the person receiving sexual gratification holding the camera him or herself—aiming it down at the actress or actor who is performing the sex act.