Tulips, hydrangea, lilacs, and other flowers offer a sweet feminine touch for your event. Go for an adult theme party that's bold and exciting with fiesta decor, spooky soiree supplies, a sun and sand theme, luau, or western party. Some other party themes for adults to try include rock and roll, casino, movie night, or mustache party. Sep 06, · Sexy Party Themes. There are several sexy themes you can pick for hosting a party that your friends will remember for some time as one of the funniest they have ever been. Here is a list of ideas that you can use as a reference but remember that what matters the most is that you make sure the theme matches your and your friends’ preferences.