Standing up, a chair, the corner of an item of furniture, or even a washing machine can be used to stimulate the clitoris through the labia and clothing. For some people, non-penetrative sex is the primary sexual activity of choice above all others. Most bisexual porn is made by small production companies rather than the major studios. As well as traditional attraction, the topic also incorporates feederism and gaining, where sexual gratification is obtained via the process of gaining body fat. Such grounds and even the definition of pornography have differed in various historical, cultural, and national contexts. Ass to mouth is a slang term primarily used to describe the withdrawal of a penis from the receptive partner anus followed by the immediate insertion into the receptive partner mouth. Lolita pornography that features actual teenage gay boy porn girls under the age of 18 is illegal in most countries and treated as child or youth pornography. Some masturbate only using pressure applied to the clitoris without direct contact, for example by pressing the palm or ball of the hand against underwear or other clothing. Patricia Hill hentai movies Collins, an African-American writer, theorizes that this is derived from a stereotype that those of black descent are promiscuous, and their buttocks are objectified by porn as a result. Some anthropologists and sociobiologists believe that breast fetishism derives from the breasts similarity to buttocks, but instead provide sexual attraction from the front of the body. A scene where many women have sex with one man is referred to as a reverse gang-bang. The slave is usually strictly forbidden from placing their lips directly on the body of the dominant so the practice routinely involves them receiving much of the spray all over their face, hair and body, however, another way of doing this that applies mostly to male dominants, is to place the mouth on the head of the penis and drink the urine as it is released. Such works have also lesbian milfs often been subject to censorship and other legal restraints to publication, display or possession.