Focus on what you do like or just move the man's hand away from the area you don't like. Sit down with your partner and read through books that describe different sexual techniques. Discuss what you both like. I see the merits of the Mars-Venus metaphor but am still a bit uncomfortable with the idea of stereotyping all men and all women. A lot of people I know agree.
Women are from earth.
To better communicate, touch your partner several times a day with kisses, hugs or holding hands. Make sure you spend quality time together often, yet at least once a week do something without your partner that is just for you. Even Gray acknowledges that he makes generalizations. He says that you will likely find some comments more fitting than others. Well, maybe, but don't count on it.