Loh Hey, the toss for prosperity!
What

When you "loh hey", you literally "toss high" the yee sang into the air several times before consuming the dish. Each toss is accompanied by a cry of "loh hey" and wishes for the New Year. It is believed the higher you toss, the more luck and prosperity will come to you.
Who
Everyone seated at the table must "loh hey". It's tradition but not only that, it's good fun. Some hilarity ensues when people wish for unorthodox blessings such as "good business for the year so I may get a big bonus". At the heart of it, the act of "loh hey" is a gesture among friends and family to invite prosperity and joy into the lives of the people they care about. It's the definition of what reunions are really about - sharing happiness.

When
The happy exclamations of "loh hey" are generally heard either during the reunion dinner on New Year's Eve, or on the seventh day of Chinese New Year, which is acknowledged as the common birthday of all humanity.
Where
There are no hard and fast rules where you can "loh hey". Generally, you do it in your home, but a restaurant will do just as well. If you want an original touch, you can even do it alfresco under the stars. Any option's fine.