Elaine Blair argues it's happening on Lena Dunham's "Girls", referencing a scene where the male character climaxes on Dunham while fantasizing she's a heroin-addicted 11-year-old girl :
Hollywood sex scenes are not typically interested in even hinting at the ways that people actually reach orgasm, and this is disheartening above all for female viewers, who develop a certain melancholy by the time that they have seen their one thousandth sex scene in which it is taken for granted that by sex we mean mutually rapturous face-to-face vaginal intercourse. Even though the only person having fun in Dunham’s scene is the guy, there is nonetheless a certain joy in seeing someone get off in some other way.
In a New York Times interview Dunham has spoken, apropos of this scene, about her male peers’ saturation in pornography, and about her own suspicions, in some intimate situations, that her partners were mimicking gestures that they had seen online. But if Adam is meant to be obviously under the influence of porn, and his moves echo a staple porn sequence, what Dunham has done with the scene suggests that pornographic convention can actually be an antidote to a certain kind of prudish Hollywood bias.
The explicit sexual nature of the show might explain why 60% of its audience is male. More analysis of "Girls" here and here.
(Video: A scene from Lena Dunham's film Tiny Furniture)