Wet in wet

Two methods of applying paint to the surface for special effect are "wet-in-wet" (or "wet-on-wet") and "dry brush". Wet-in-wet is used to avoid a hard edge at the margin of the paint. Wet-in-wet paint flows on a wet surface. The paint is wet (diluted) and the surface of the medium is wet.
The surface of the paper or other medium is first "painted" with water, thinned paint is then dripped or lightly applied to the wet surface. The color flows along the wet area. More paint can be added to increase the area covered.
After the first wet application has dried, additional wet layers can be applied. The flow is controlled to some extent by the wetness of the surface; the amount, consistency, and placement of the paint; and by tilting the surface to encourage the paint to flow in the desired direction. The somewhat unpredictable results of the wet-in-wet technique can lead to some surprising but welcome effects.