I didn't read the pic as sexual... I mean, yes, they are naked but... For me, the pic is symbolic of relationships in which the woman is leading the way, the man is meant to serve the woman... Instead of the more tradional role in which the woman serves the man.
It reminds me of this time in NYC when I saw pop singer Madonna come out of a car with her now ex-husband Guy Ritchie. He had to open the door for her, wait for her to come out, all the attention was on her, the camera flashes eating her up, the people were shouting her name. He held her by the hand but was somewhat walking behind her...
There are some relationships out there in which you get the sense that more value is placed on the woman, her ideas, her needs, her wants, her decisions. Maybe the guy gets a sense of pleasure out of making the princess happy... I don't know. Personally, I could never be in a relationship like that.