I decided to go with a flesh tone on the dragon's underbelly, balls, and cock in this one, as I was going through an exposed flesh fetish (which explains the pinkish balls on the buck; they're not completely bare, but the fur's thin enough to show the pink underneath :)  Putting the spots on the dragon while colouring with the markers was neat to do, as was the transparency effect on his membranes (done by first colouring what would be underneath, then going over that with the marker that's the colour of the membrane).