She applied the stain with a rag, wiping it in circles. Her heart sank. The result was blotchy. The oak grain was drinking the liquid unevenly, turning the leg into a patchwork of muddy reds and pale blondes. It looked like a bruise.
It was barely three seconds of movement. The dark glaze settled into the pores of the wood, mimicking the natural aging process, tricking the eye into seeing depth where there was only flatness. The bruise vanished. The color evened out, settling into a rich, warm tone that looked a hundred years old. A Little Dash of the Brush
While not a fixed idiom, the phrase appears in art criticism and studio guides from the 19th and early 20th centuries. For example: She applied the stain with a rag, wiping it in circles