Recently, I was talking to female rubber fetishist from the west coast. She was giddy over how many girls are screwing their "under 23" boyfriends from behind. While not typical, she thought it was increasingly common.
I once overheard a girl yell in club: "If you want to fuck me up the ass that's fine, but I get to do it to you. Its your decision."
I agree with Elise Sutton that many men are changed after being penetrated anally. So, if this trend goes wide it is a major development in the world of sexuality.
Speaking of Elise Sutton, recently, she received a letter purportedly from a woman who teaches sexual education at an all girl school. The teacher surveyed her students within guidelines and found several surprising results. Following up, she found a large number of the women were virgins especially among her "advanced placement" students. Upon further questioning, it turned out they are telling the boys to get down on the muffin if they wanted some lovin'. And, the boys were complying.
If young women start demanding cunnilingus without giving their boyfriends any expectation of further sexual activity, then this is an amazing shift in sexual power. Also, it could be a milestone on the way to normalizing bisexuality and cuckolding among American women.