Sex Appeal is a stat that you can increase through actions in the game, which allow you to change your interactions with the female NPCs in the game, with a big part being the Girlfriends. However, unlike some of the stats in the game, you may notice that Sex Appeal can jump around a lot, as it isn’t one that you can steadily increase or decrease to have it permanent. The reason for this is that there are certain factors that change Sex Appeal, such as the clothes you’re wearing, the car you’re driving, and other appearance-related things. Generally, you will want a sports car, as well as the most expensive clothes, which are available at Didier Sachs. Note that the car’s condition also has a factor, and there is a radius around the vehicle that maintains the Sex Appeal boost. You will need to max out the Sex Appeal bar to unlock this trophy/achievement.