Not very often, in fact, sex appeal in games for me is most often a bonus, something sparse that I probably did not originally know was going to be there at it's best, and like most of the "sex appeal" games out there so over the top with sex that I found it disgusting at it's worst. I like sex better if it's treated as more of a here and there thing in games as a reward for doing something, not as the core of the entire game itself and the only thing it has to stand on.