Easiest way in 1/72 is to find a pencil the same or as close as possible to the colour you need and use that to draw your squiggle on.
It is best to apply a flat clear finish first, it gives something for the pencil to 'bite' onto.
With just the right amount of pressure, you'll get the appearance of a sprayed application unless you look REAL close.
I stumbled on this method when trying to do squiggle on my 1/48 Hs-129.
In 1/48 it looked drawn, but for 1/72 it would be perfect I think.