The niche popularity grew significantly in gay boy porn the latter half of the first decade of the 2000s. Pornographic films are typically categorized as either softcore or hardcore pornography. Bukkake is a sex act portrayed in pornographic films, in which several men ejaculate on a woman, or another man. 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. Starting with erotic stories and woodblock prints from before the 20th century, Japanese pornography evolved into distinct subcategories with the media that in addition of pornographic videos and magazines featuring live actors, there is exist categories of pornographic manga , pornographic computer games , and pornographic anime . Some pornographic films use an artificial semen substitute to simulate or enhance creampie shots. A woman can use a secondary vibrator, between the dildo and her genitals, milf fuck to get pleasure from pegging. Spanking can be administered in a number of spanking positions. Threesome can also refer to a love triangle, hentai porn a three-way romantic relationship. Some may keep their hand stationary while pumping into it with pelvic thrusts in order to simulate the motions of sexual intercourse. Diaper fetishism is totally independent from pedophilia as the wearer derives pleasure only from the diaper and/or use of it. Normal quantities of ejaculate range from 1.5 to 5.0 milliliters . It is also known colloquially as gushing or squirting, although these are considered to be different phenomena in some research publications. Many fantasies include the macrophile shrinking before a normal sized woman or keeping his or her normal height while the partner grows in size. For much of the history of cinema and television, lesbianism was considered taboo, though since the 1960s it has increasingly become a genre in its own right. Content featuring male bisexuality has been a growing trend since the advent of internet pornography.