4.5mm Plastic Medium Tips Paints Marker Pen Blank Tube Ink Refill Pen
Marker Pen Airbrush System
Wicked colors paint (no Airbrush Paint Reducer )
(all on ebay)

the tube may not fit into the Marker Pen Airbrush but just heat up the holder and push it in and let it cool down.
(note: Createx Wicked Colors are WaterBased so it need to dry up before dip)
..easy - fast - no clean up airbrush...
(dont forget to wash soft bait with a few drops of detergent before airbrush)