Now comes the actual felting. Lower your wool-wrapped plastic pattern piece into the warm, sudsy dishwater. This will help open and close the barbed fibers in the wool, much the same as a washing machine set to warm will felt a sweater.
The other factor for felting is agitation: gently move the piece through the water, rubbing and handling it until the wool begins to shrink around the pattern. In a few minutes, you should begin to see a recognizable stocking.