This sign can be used in a lot of ways! When used in its proper way it means that you have “already done” something. If someone asked you: ‘Did you wash the dishes?” You could sign “yes” or you could sign “finish” meaning, “I’ve already done them.” In its more “slang” or idiomatic way, the sign can be used by a harried mother who has told her children, repeatedly, to stop doing something. It’s a fun sing and can be used in many ways.
American Sign Language - Joy's way 