Book excerpt: It's the essential guide to dressing to undress, from the basics of bras, panties, slips, and shapewear to the sexy extremes of corsets, sheer chemises, balconets, and bustiers--perfect for the tens of millions of fans of Fifty Shades of Grey who are now wondering what to wear. Written by lingerie expert Rebecca Apsan ("the best bra-fitter in the country"--New York magazine), Lessons in Lingerie covers it all: The revelation of a properly fitted bra. How to cultivate your inner coquette. How to look ten pounds thinner. What works under a clingy dress or a sheer white blouse. The basics of shopping, cleaning, organizing. And Ms. Apsan's manifesto for change: Stop wearing underwear!