It probably comes with years. When i was a young stallion there was nothing sexier than a completely nude female to me.
The more years pass by the more refined personal definition of sexy becomes. I am not completely sure why and what has influence on that, but elegant and yet "bitchy" is so much more sexy to me now, than a completely nude :)
Click to enlarge
Shot with Nikon D3s 50mm 1.4G f/8 1/250 iso 200
Have fun,
David