That’s Serge Gainsbourg and Jane Birkin. Photo was taken sometime in the 1970s, I’d guess.
As a psychological experiment, its raw unapologetic essence can’t be topped for rudely revealing the fundamental psychosexual difference shaping male and female desire. Both men and women — at least normal, sexually dimorphic men and women and not bitter androgynous blobs — would feel sexually aroused by this photo.
Which really says all you need to know about the sexes. Men are aroused by the sight of a beautiful woman submitting to a dominant man administering disciplinary blows to her backside. Men imagine themselves in the role of the man in the photo, and become excited.
Women are aroused by the sight of a dominant man exerting his uncompromising power over a vulnerable woman surrendering to her punishment. Women imagine themselves in the role of the beautiful woman in the photo, and become excited.
If you could only know one thing about women, this photo, and how men and women react differently to its stimuli, is sufficient to guide you through life.