You mentioned you're taking baby steps with her. Now that she has been out with a remote controlled clit vibe, have her remove her panties (either there at the table or in the ladies room) and have her place them so that they hang out of her open purse which should be sitting on the table. The waitress/waiter would then be able to see them every time they came up to the table. Of course, you'll be running the risk of being kicked out of the restaurant.
Another thing to have her do would be to wear a somewhat short summer dress with no panties and then go to a mall that has a glass elevator and have her ride the elevator up while leaning against the glass. You could even stay at the bottom level and point her bare ass out to some young men.
Dear lady, you have an evil mind. Now where can I find a glass elevator?