It means you get involved. Technically, our local forms of government are not participatory democracies. Officially, participatory democracy is direct democracy, in the sense that all citizens are actively involved in all important decisions.
It shouldn't if washed with gentle care. Rayon is a cellulose fabric and like most cellulose fabrics, it may shrink when washed. If the manufacturer has indicated the garment should be dry cleaned only, do not push your luck. If it is hand-washable though, you can use the gentle cycle on your washing machine and Woolite to get the job done.
Rayon is the generic term for fiber (and the resulting yarn and fabric) manufactured of regenerated cellulose by any one of six processes. Its importance as a fiber lies in its versatility, and in the fact that it was the first viable manufactured fiber.