Most bisexual porn is made by small production companies rather than the major studios. In S/M, the Sadist is usually the Top and the Masochist the Bottom, hentai movies but these roles are frequently more complicated or jumbled . The volume of semen that is ejaculated depends on several factors, including the male health, age, degree of sexual excitement, and the time since his last ejaculation. John Stagliano is considered to have started the gonzo pornography genre with his Buttman gay movies series of films. The strategies and tactics that are used to smuggle one of the couple into and out of the toilet undetected are as important or almost as important as the urination. The reverse of this, in which nude women interact with clothed men, is called Clothed male, naked female . Clothed male, naked female is one-sided female nudity in which one or more females are nude while one or more men are clothed. The name is a reference to gonzo journalism, in which the reporter is part of the event taking place. The name was coined from the title of the controversial book. They further argue that setting a discrete line between safe and not-safe activities ideologically denies consenting adults the right to evaluate risks vs rewards for themselves; that some adults will be drawn to certain activities regardless of the risk; and that BDSM play—particularly higher-risk play or edgeplay—should be treated with the same regard as extreme sports, with both respect and the demand that practitioners educate themselves and practice the higher-risk horny milfs activities to decrease risk. If this is done using penises and/or strap-on dildos, this is sometimes called the sandwich or BigMac. Though there have been numerous gang bang pornographic films since the 1980s, they usually involved no more than half a dozen to a dozen men. 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.