Painting screaming faces

[Wombat85]

Can anyone point me toward a guide on how to paint screaming faces typical in chaos space marine models. Something like the freehand faces on this:

http://www.coolminiornot.com/332383?browseid=7249805

 

[Dragonsreach]

I know how to do the GW Demonic style faces easily enough.
First practise on flat surface, with very thinned paint draw a box (rectangle) then above each top corner draw triangle with one point almost to the middle of the top line of the rectangle. Do mirror image.
Above triangles paint wide "U" shape.
These are your starting points from these shapes blur out to form facial structure raising highlights ALWAYS using very thin paint.


Sorry I can't give a demo, 1 its 04:30 Friday morning, 2 I'm using a touchpad.

 

[Demihuman]

Also there is this: http://chestofcolors.com/how-to-paint-rasputina-tutorial/ Not the same faces but Ana explains her technique in-depth. I bet you could get a diagram out of Mr. Dragonsreach as well after he gets a good nights's rest.