John Stagliano is considered to have started the gonzo pornography genre with his Buttman series of films. Foot fetish pornography features heavy emphasis on the feet of the participants, either in combination with kissing and genital sex or in the context milf fuck of acts such as trampling or crush fetishism. A few extremely flexible males can reach and stimulate their penis with their tongue or lips, and so perform autofellatio. If this is done using penises and/or strap-on dildos, this is sometimes called the sandwich or BigMac. Originating in Japan in the 1980s, the genre subsequently spread to North America and Europe, and crossed over into gay pornography. Incest itself is largely taboo, and is a crime in many countries. A somewhat controversial ejaculation control technique is to put pressure on the perineum, about halfway between the scrotum and the anus, just before ejaculating. Cuckolding can also be mixed with other non-monogamous relationship arrangements with which it has substantial overlap such as Swinging, wife-swapping, open relationships, and polyamory, etc. Older videos gays names for a pornographic film include stag film, and blue movie. Sadomasochism is practiced in isolation relatively rarely, though some hentai porn masochists report biting, pinching, or even stun-gunning themselves as a prelude to, or as part of, masturbation. A homosexual threesome would involve either three men or three women. 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. Pornography is often distinguished from erotica, which consists of the portrayal of sexuality with high-art aspirations, focusing also on feelings and emotions, while pornography involves the depiction of acts in a sensational manner, with the entire focus on the physical act, so as to arouse quick intense reactions. The act may be carried out face to face, or head to tail, with the woman recommended to be on top if she has smaller breasts.