Like all scenes, this too can be approached in a variety of different ways.

This one explores the psychology of power exchange. One of you agrees to be the submissive for the evening; the other is the dominant, the maestro, the one whose word is law. You go out for an evening on the town--a formal dinner, perhaps, and maybe a movie afterward.

The dominant should establish a few rules beforehand; for example, the submissive is not allowed to speak to or have any contact with anyone except the dominant. So, for example, when you're ordering your meals in the restaurant, the submissive cannot tell the waiter what to bring; he or she must tell the dominant, who will then tell the waiter. (Or, you can turn this around; the dominant speaks to nobody except through the submissive.) Rules like this are fun to play with, because while the people around you may notice something is going on, the won't know exactly what.

As the evening progresses, the dominant can find all kinds of delightfully subtle ways to tease the submissive.   Perhaps he'll tell her to go to the ladies room and remove her underwear, the better to tease her in a darkened theater. Maybe he'll order her not to come back out until she has thoroughly aroused herself.  Or perhaps she'll have to wear a sex toy of some sort under her clothes. Maybe during dinner he can whisper to her what he's going to do to her when they get back home.  

The key to enjoying this kind of scenario is to keep it quiet; it's great fun if nobody else has the slightest idea what's going on. (To an aroused submissive, it will seem like it's obvious and that everybody knows what's happening--and that's part of the fun!) 

Just remember to play safe and have fun!