The sign for "happy" is made by placing one or both of your hands in front of you.
Use "flat" hands, palms pointing back. Circle your hands forward, down, back, up, forward, down, back, up. Both hands move at the same time and in the same direction. On the upward swing the hands are very close to your chest or touch your chest. On the downward swing your hands are further away from your chest.
Note: Some people slightly "slap" the chest - other people don't even touch.
Note: During casual everyday use this sign is sometimes done with just one hand. When used in the song "Happy Birthday to You" it is typically done with two hands.
All material copyright © 1996 by Dr. William Vicars