What seems clear from the historical record is that much of the lesbian material in pornographic texts was intended for a male readership. Biological anthropologist Helen B. 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. Older names for a pornographic film include stag film, and blue movie. Such ejaculation can be done by mammary intercourse, or masturbation over the other person, or result from the withdrawal of the penis from a partner mouth as he is ejaculating following fellatio, irrumatio, or intercourse. Multiple men and women Bisexual pornography features one woman and two men who all perform sex acts on each other. 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. Evolutionary psychologists suggest that rounded buttocks may have evolved to be desirable trait 3d hentai because they provide a visual indication of the woman youth and fertility. Sexual orientation Pornography features an increasing variety of combinations of actors by their sexual orientation such as lesbian, gay, bisexual, and transsexuals in addition to traditional heterosexual roles. Content featuring male bisexuality has been a growing trend since the advent of internet pornography. The industry generally refers to such films as adult films, which is part of adult entertainment. John Stagliano is considered to have started the gonzo pornography genre with his Buttman series of films. Though there have been numerous gay fuck gang bang pornographic films since the 1980s, they usually involved no more than half a dozen to a dozen men. Some straight actors have started acting in gay porn only mature milfs to be accused of being gay while others first step was to strictly do solo scenes. Macrophilia is a fascination with or a sexual fantasy involving giants, more commonly expressed as giantesses .