Female masturbation involves the stroking or rubbing of a woman vulva, especially her clitoris, with an index or middle fingers, or both. The fantasy is typically based around one or more larger beings dominating a smaller being. Biological anthropologist Helen B. Crush pornography features objects being crushed by an actress or actor, who generally plays an overtly dominant role. Some aspects of the research community distinguish between female ejaculation and what is colloquially known as squirting or gushing. Kurt Wild, who appeared as a bottom in Lucas Entertainment Gigolos, is married to a woman and has three children. John Stagliano is considered to have started the gonzo pornography genre with his Buttman series of films. Both sexes sometimes apply lubricating substances to intensify sensation. Pornography may fall into more than one genre. 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. Felching is a sexual practice involving the act of orally sucking semen out of the vagina or anus of one partner. Spanking can be milf xxx administered in a number of spanking positions. Some pornographic films use an artificial gay twink porn semen substitute to simulate or enhance creampie shots. Such grounds and even the definition of pornography have differed in various historical, cultural, and national contexts. Group sex pornography features at least two men and two women , usually more, who all perform sex acts on each other. Internal ejaculation gay hentai shots are a comparatively recent development in pornography; they are not found in early pornographic films. In some creampie films, both gay and straight, intercourse and internal ejaculation are followed by performers licking up the semen that has dripped from their bodies. This genre also features male-on-male fellatio through a small hole made in a bathroom divider. The act may be carried out face to face, or head to tail, with the woman recommended to be on top if she has smaller breasts.