Teacher and Student or Boss and Secretary pornography involves sexualized situations which take place between an authority figure, such as a teacher or boss, and an underling, such as a student or secretary, often fake. They cited the Internet and text messaging as common ways of organising meetings. This milf fuck is commonly called double anal or double stuffing. Arousal may be triggered by seeing the body movements or facial expressions of that person. Since at least 1973, it has also been used to refer to a sexually attractive young woman. Performers are usually clean-shaven, thinner and more effeminate than ones in mainstream gay pornography. Body parts including fingers, tongue and penis may be used for anonymous oral, vaginal and/or anal intercourse. While most tentacle erotica is animated, there are also a few live-action movies. Rape itself is a crime in many countries. Going back at least as far as the Christy twins in the 1970s, depictions of incest and particularly incest between twins has been a feature of gay pornography. Sex experts have praised various techniques that the performer can use during fellatio to increase their partner pleasure. Although pornography has usually focused on heterosexuality, due to the prevalence of the heterosexual orientation, explicit gay material has a long history as well, which reaches back to Greek antiquity, if not to prehistory. Others involve partners who naturally have gay twinks a significant difference in size. The Japanese sex industry uses the term Paizuri . The name of the practice, when it is done in a repeated in-and-out motion, is derived from its passing resemblance to the dipping of a tea bag into a cup of hot water as a method of brewing tea. The terms can be complimentary or pejorative. Some productions are noted for sophisticated and/or experimental storytelling and animation techniques. Often a dominant woman, she may be called a Dom, Domme anime hentai /ˈdɒm/, Femdomme, Domina, or Dominatrix, depending on context or personal preference.