The strings and bridge exert quite a lot of pressure on the snakeskin of your Erhu. After a while, the snakeskin will start to sag. To prolong the inevitable, it is a good idea to remove the bridge when you are not using. However, moving the bridge frequently might damage the snakeskin and also disrupt the rapport and harmony that the bridge has formed with the snakeskin over time.
Thus, a good idea would be to put something between the strings and resonator to relieve some of the pressure.
You can use a dowel like object,
or take a pencil and roll it with masking tape,
or take a long tube and slot it right above the bridge(material used with compliments from Clyde of Hawaii).
