Creampie scenes depart from heterosexual pornographic convention in favor of a depiction that more closely mimics sexual intercourse as performed in ordinary life; they have been called the counterimage of facials. What seems clear from the historical record is that much of the lesbian material videos porno gay in pornographic texts was intended for a male readership. Although interracial pornography theoretically can apply to depictions of sexual activity between performers of any different racial groups, the term is most commonly used for heterosexual sex acts between black and white performers. Transsexual porn star Wendy Williams has stated that transsexual Porn is classified as Straight Specialty. Jerk off instruction hentai movies features a performer encouraging or instructing the viewer to masturbate, often culminating in a countdown at the end of which the viewer is invited to induce orgasm. Use of the agreed safeword is seen by some as an explicit withdrawal of consent. Internal ejaculation shots are a comparatively recent development in pornography; they are not found in early pornographic films. Solo pornography recognized with nude milfs AVN Awards include the All Alone series and All Natural: Glamour Solos. The existence of such content in commercially available pornography is widely considered an urban legend. It is used, for example, at fertility clinics to stimulate sperm donors. Other objects such as ball point pens and thermometers are sometimes used, although this practice can lead to injury and/or infection. Both forms of pornography generally contains nudity. Such explicit sexual interaction is seen only rarely in public play spaces, and it is sometimes specifically banned by the rules of a party or playspace. Multiple men and women Bisexual pornography features one woman and two men who all perform sex acts on each other. It has also been recommended as a form of foreplay or safer sex. Detective magazines, comic books and early fetish magazines In the early 20th century, Detective magazines covertly provided a way of publishing bondage imagery.