Bondage pornography specializes in the depiction of sexual bondage or BDSM activities as photographs, stories, movies, or drawings. Commenting on why there are not as many female macrophiles, psychologist Helen Friedman theorized that because women in most societies already view men as dominant and powerful, there no need for them to fantasize about it. The fantasy is typically based around one or more larger beings dominating a smaller being. Such ejaculation can be done by mammary intercourse, or masturbation over the other person, or result from the withdrawal of the penis from a partner mouth as he is ejaculating following fellatio, irrumatio, or intercourse. While some fantasize about a giantess who is slightly taller than himself, others are interested in giantesses that are hundreds or even thousands of feet tall. Female masturbation involves the stroking or rubbing of a woman vulva, especially her clitoris, with an index or middle fingers, or both. Production of such films was profitable, and a number of producers specialised hentai movies in their production. Being forced to wear diapers as a form of humiliation is sometimes a behavior encountered in sexual masochism. These actors often play the top roles but this is not always the case, such as with Kristen Bjorn and some Bel Ami models. Many transgender people regard the term shemale as offensive, arguing that it mocks or shows a lack of respect towards the gender identity and gender expression of transgender individuals; in this view, the term emphasizes the biological sex of a person and neglects their gender. Cartoon pornography is the portrayal of videos porno gay illustrated or animated fictional characters in erotic or sexual situations. Cartoon pornography depicts illustrated or animated fictional characters in erotic and sexual situations. Some people get sexual pleasure by inserting objects, such as urethral sounds, into the urethra , a practice known as urethral nude milfs play or sounding. Today, pornographic films can be sold or rented on DVD, shown through Internet and special channels and pay-per-view on cable and satellite, and in adult theaters.