Making her happy doesn't always have to be a mystery. For years, the clitoris was considered the only trigger for the female orgasm. Alas, even finding the clitoris turned out to be a daunting task for many men, and things didn't get any easier in 1950 when a physician by the name of Dr. Ernst Grafenberg found an even more mysterious female pleasure spot hidden within the vagina.   This area became popularized by sexologists in the 1980s as the "G-spot." It turns out that stimulation of the G-spot produces a very powerful kind of female orgasm; and in some...