You make me blush, people, it's a damn silly technique. Here it goes: white basecoat, add any other colour. Let dry. Apply a mix of:
1/2 water
1/4 Vallejo black glaze
1/4 Vallejo slow dry
Let dry. Over.
With a little practise you are going to paint 10 miniatures like that in an hour. The magic dip is an option, but you don't always want the brownish hue to show. I'm told the new GW Glazes do the job as well.