This video was taken at 1921. This video shows how Glazing was done by dipping at early stages of ceramic sanitary ware production.
As we can see the video. The Glazer takes a Green Sanitaryware body and puts in a tub filled with glaze. He immerses and rotates the Sanitaryware into the glaze. just after few seconds he takes out the ware and drains the excess glaze. In corner areas, he uses the brush to remove the excess glaze.
The glaze used in this method of glazing is less viscous because the draining of the glaze should be fast to avoid wavy in glaze application.