The finger bowl was once used with regularity. It is a bowl of warm water filled half way, used for rinsing your fingers, usually after the main course, just prior to the dessert course.
It is served on a service plate with a paper doily placed between the bowl and the plate. A fresh dinner napkin is placed either on the plate or at the left side of the service.
When served in this manner, the “event” may be referred to as a course. For example, if three prior courses of soup, salad, and a main course (lobster, perhaps) are served, it would be referred to as a fourth course (a cleansing course), the fifth being dessert.
The bowl, on its service plate with napkin included, is placed in front of the diner after the previous course has been removed.
A rose petal or a lemon slice may be placed in the warm water.
Finger bowls are nice to include as a special touch when the main course consists of food that can’t be eaten entirely with a fork and knife and involves the fingers. Consider the aftermath of lobster or corn on the cob, or any other food where fingers are utilized.
If not familiar with the custom, you might mistake this "course” for another soup course. It has happened at many a dinner table. But remember, a soup course will not be served with its own napkin. A finger bowl is served with its own napkin.
Place the clean napkin folded in half just as a normal napkin is, underneath the napkin you have been using. The used napkin will be for wiping your fingers after dipping in the finger bowl.
With one hand (doesn’t matter which first) placed between the first and second napkins, lift that side of the napkin to the edge of the table, while simultaneously dipping the fingers of the other hand directly into the warm water. (Resist the temptation to swish your fingers around.)
Bring the fingers directly onto the napkin and gently wipe them without lifting the napkin.
Repeat with the other side.
When finished, take the used dinner napkin, which has just been used to dry the dipped fingers, and fold it loosely. Then place it on the left side of the service plate.
A server will remove the plate and napkin. At this moment, make sure your new napkin is on your lap ready to go, free of any evidence of use.
Your dessert silverware is ready in the main course area.
The server will bring your dessert soon.
Most restaurants don’t use finger bowls anymore, but when they do, the bowl often comes with a tightly folded hot damp wash cloth on a service plate. In less expensive restaurants, packaged towelettes do the job.
I like using finger bowls if a dinner or lunch is messy even though, as Miss Manners explains of the tradition, "Correctly used, the finger bowl is a charming touch of no practical use whatsoever."
Regardless, little white damask or glass bowls work well. And I like to use a pretty luncheon paper napkin, as diners can leave their dinner napkins on their lap. I explain to my guests, “Here is your finger bowl and a napkin to use for a drying purpose." Most diners will ask how to do it, and I just say, “Dip the fingers of one hand into the bowl, don’t swish or play, wipe your fingers with the paper napkin, and then switch to the other hand.”
Once you've experienced this little treat, you'll understand why it has stood the test of time. And why it is so much more fun than a towelette!