Cum-shot pornography features a collection of male ejaculation scenes. It is sometimes described as a sexual fantasy, by women or men, depicting hentai sex an exhibitionist or physique worship scenario. There are currently no known laws forbidding the crushing of objects and insects, however the production or trade of crush erotica involving live vertebrates is condemned by animal rights activists and is illegal in many countries, including the United States and Great Britain. It may also involve touching, rubbing, or pinching the nipples or other erogenous zones while masturbating. The nipples are erogenous zones, and vigorous stimulation of them during masturbation usually causes the penis to become gay movies erect more quickly than it would otherwise. 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. As in B/D, the declaration of the Top/Bottom may be required, though sadomasochists may also play without any Power Exchange at all, with both partners momsex equally in control of the play. Rough sex pornography is similar to pornography featuring sadomasochism, and typically features a Top who humiliates and/or degrades a Bottom while being physically violent towards them. Fantasies of group sex are extremely common among both men and women, and group sex is a subgenre in pornographic films. Within a BDSM or D/s context, facesitting can be an especially intense form of erotic humiliation. Can also include auto-fellatio, or performing oral sex on oneself. It may involve sexual attraction to women who are pregnant or appear pregnant, attraction to lactation, or attraction to particular stages of pregnancy such as impregnation or childbirth. They may repeat this cycle multiple times. A variant of this is known as ATOM or ATOGM where the insertive partner removes his penis from one recipient anus and inserts it into a second recipient mouth. 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.