“While sex education was not a topic freely discussed in ancient China, it was nevertheless important for newlyweds to have a basic understanding of what they should do on their wedding night in order to fulfill their obligation to family and society to have sons. There were several ways to accomplish this but one method was to provide the bride with a coin which displayed the basic sexual positions.
These marriage coins or charms usually had an innocuous inscription (legend) such as “Wind, Flowers, Snow, Moon” on one side. The reverse side of the coin would depict one, two, or four couples making love in various sexual positions…
The Chinese usually refer to these coins as mixiqian (秘戏钱) which means “secret play” or “secret fun” coins. They are also known as bi huo qian (避火钱) which means “hide (evade) the fire (of lust) coins”. In English, they are variously referred to as Chinese marriage coins, Chinese love coins, Chinese spring money, Chinese erotic coins, Chinese wedding coins, etc.
As mentioned, these coins are sometimes called “spring” (chun 春) money. This refers to the ancient Chinese springtime ritual, where boys and girls separated by a stream would sing love songs to each other…”