This is a term I coined for a particular technique I used while washing windows professionally. Typically, the mop (a T shaped piece of plastic with a fuzzy sleeve around the top of the T) is dunked in a bucket of soapy water before being applied to a window. Instead, I kept only clean water in my bucket and applied dots of soap directly to the mop. This resulted in a dramatic reduction in soap usage.
This technique will become vital if soap prices ever skyrocket. At the moment most do not consider it worth the hassle.