This type of pornography is almost exclusively hentai, as true hermaphroditic humans are not fertile and are not usually found in nature. Among swinging couples, one of the two anime hentai partners is often the driving force and the other is more passive-supportive of the addition of additional sex parties. Femdom features BDSM scenes in which the dominant partner is female. Transsexual porn star Wendy Williams has stated that transsexual Porn is classified as Straight Specialty. Once insertion is complete, the fingers are either clenched into a fist or kept straight. Transgender pornography features performers who cross-dress for sexual gratification, either for themselves or for their partners. In the 18th and 19th centuries, some European theologians and physicians described it as heinous, deplorable, and hideous, but during the 20th century, these taboos generally declined. In the fetish cuckolding subculture, it is most common for the female to take on the sexually dominant role and the male the submissive role, however, female subs, sometimes referred to as cuckqueans, also exist. It is typically animated pornography, as the legal age to be featured in a pornographic film in Japan is 18. Hermaphrodite, also known as herm, refers to pornography, typically hentai, that features persons with the genitalia of both sexes. Voyeur pornography may also include shots momsex of topless women on topless beaches who are unaware of the cameras but may legally be photographed due to the public setting. 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. Lolita pornography features women who are 18 years old or slightly older, who pretend to be underage teen girls. However, bisexual pornography is often placed near the gay section in adult video stores, gay cock since many consumers are gay men. Some people get sexual pleasure by inserting objects, such as urethral sounds, into the urethra , a practice known as urethral play or sounding.