There were also a very limited number of specialist fetish magazines which featured images of bondage, such as the famous Bizarre magazine published from 1946 to 1959 by the pioneering fetish photographer John Willie, and ENEG Exotique magazine, published 1956-1959. The nipples are erogenous zones, and vigorous stimulation of them during masturbation usually causes the penis to become erect more quickly than it would otherwise. However, the tradition of bondage magazines continues in the form of art books of bondage photographs, published by mainstream publishers such as Taschen. The term soft crush refers to the more common fetish surrounding videos involving inanimate objects or small invertebrates being crushed, while the term hard crush refers to such videos involving larger animals with vertabrae, and arguably more pain-susceptible animals . Ass to mouth pornography shows the transfer of a performer penis from a second performer anus to that same second performer mouth in a single shot. 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. Transsexual porn star Wendy Williams has stated that transsexual porn is classified as Straight Specialty. The inside of a smotherbox is often padded to provide support for their neck and prevent their head from moving. The consent and gay twink porn compliance for a sadomasochistic situation can be granted only by people who can judge the potential results. The term is a slang word that originated in the gay community and comes from the equestrian term bareback, which refers to the practice of riding a horse without a saddle. Male masturbation may differ between males who have been hentai videos circumcised and those who have not. 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 equally in control of the play. Reality nude milfs Reality pornography refers to real or faked amateur encounters.