Spray the paint pad with water, which will allow you to manipulate the mixture better before it dries. Dip the pad into the paint mixture (less is more with this technique, so don't overload it), and apply it to the wall using one long, continuous vertical stroke.
Almost as soon as that paint goes on, apply a fair amount of pressure to a dry bristle brush and drag it through the mixture (use the smaller brush in tight areas). Keep it dry by rubbing the brush with a rag between strokes. Overlap each stroke just a bit and if it looks like there's too much paint, wet the brush; wipe it off, and then lightly brush the area.
Note: Avoid overworking the paint. Too much water can muddy the streaking effect you're trying to create.
Continue in this fashion until the desired area is finished, and let it dry completely.