It is really sexy and it is a good way to let me desire muche more the time we will go out of the restaurant.
Obviously it must be done naturally, nhot only to show how sexy a woman can be even in public. If it is natual, the world is closed between the two lovers and no one exists anymore.
Usually I like this when it happens.
It can increse the desire without being able to satisfy it immediatly: a really pleasant suffering. ;)