One or more of the participants may engage in autoerotic sexual activity, such as masturbation, possibly without physical contact with the other participants. In some societies, the terms fox, plum, chick, or chicken are preferred. The person sat upon gay movies may be in bondage, sexually submissive, or simply held down by the body-weight of the other person. When all regions of the face are included, facial cum shots comprise approximately 62% of scenes where external ejaculation occurs. 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. A somewhat controversial ejaculation control technique is to put pressure on the perineum, about halfway between the scrotum and the anus, just before ejaculating. Such films continued to be produced but could only be distributed by underground channels. The stimulation may involve hands, fingers, everyday objects, sex toys or combinations of these. It is commonly depicted in pornography, but very rarely in mainstream cinema. The inside of a smotherbox is often padded to provide support for their neck and prevent their head from moving. When he is in position the cover is closed. Said that the female buttocks evolved in the context of females competing for the attention and parental commitment of powerful resource-controlling males as an honest display of fat reserves that could not be confused with another type of tissue, although T. Internal ejaculations, followed by lesbian hentai images of semen dripping from the anus, are sometimes depicted in bareback gay pornography, nude milfs where they are referred to by the term breeding or the reverse money shot. Some restrict a policy of panties/nipple tape for females and some allow full nudity with explicit sexual interaction allowed. Pegging is a sexual practice in which a woman performs anal sex on a man by penetrating the man anus with a strap-on dildo. Along with the penis, the scrotum is sensitive and considered to be an erogenous zone.