All you need to have is a liquid that can transfer heat, and which can be carried to the cutting edge of the bit, while not boiling and not causing a build up of shavings. Even drilling in a pool of water works well enough, though it can be messy. If you are unlucky the cutting fluid will be your blood if you either have not held the workpiece with a holder, or it comes loose and whips around.
Working at an angle or upside down best is cutting paste or grease, as it will stick to the surface.