Pornographic films are typically categorized as either softcore or hardcore pornography. 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. In some creampie films, both gay and straight, intercourse and internal ejaculation are followed by performers licking up the semen that has dripped from their bodies. Exhibitionism: Becoming noticeably desperate gay hentai or wetting oneself with the express purpose of being seen by strangers. Evolutionary psychologists suggest that rounded buttocks may have evolved to be desirable trait because they provide a visual indication of the woman youth and fertility. However, gay pornography in the modern world is mostly concentrated in the making of home videos , cable broadcast and emerging video on demand and wireless markets, as well as images and movies for viewing on the Internet. Yuri : Featuring two grown adult women in a homosexual/lesbian relationship. Double penetration of the vagina, anus and mouth, can involve: Simultaneous penetration of the anus by two penises or other objects. Among swinging couples, one of the two partners is often the driving force and the other is more passive-supportive of the addition momsex of additional sex parties. Some anthropologists and sociobiologists believe that breast fetishism derives from the breasts similarity to buttocks, but instead provide sexual attraction from the front of the body. The term has also applied to other professions and even companies trying to appeal to a gay gay twink porn demographic. Clothed male, naked female is one-sided female nudity in which one or more females are nude while one or more men are clothed. A study of 164 males in Finland from two SM clubs found that 18.2% had engaged in coprophilia; 3% as a sadist, 6.1% as a masochist, and 9.1% as both. 18% of heterosexuals and 17% of homosexuals in the study pool had tried coprophilia, showing no statistically significant difference between heterosexuals and homosexuals.