I'm sure this is not a new technique, but I have just discovered it and love it! I found a Zig Aqua pen at Michaels a few weeks ago and decided to give it a try. For this technique you really need to use watercolor paper. It's specifially made to hold up being wet and not curl and the colors do not bleed. You can find the paper in the artist section of any craft store.
Just stamp your image using a waterproof ink (I like Ranger Archival Ink) and then take the aqua pen and swipe it across your distress ink pads and fill in your entire image. It's so easy to blend and layer color this way. Once the image is colored, just cut it out and you're ready to add it to your card or layout. Super easy!