When mixing growing medium, it can be as wet as you like to make it for easy mixing. Sometimes a little wetter helps to evenly disperse the various ingredients when you mix it with your hands, stick, spoon, whatever. Steaming it in a microwave also helps to both sterilize the medium (to hopefully prevent moss and fungal growth) and to moisten those stubborn little clumps of dry sphagnum moss.
However, for planting, it is often easier to sift growing medium that is dry-to-just-moist around the roots and bulb than to try to stuff clumpy wet or overly moist growing medium into the planter with the Flytraps. So--
- For mixing: wetter sometimes makes it easier
- For planting: dryer usually makes it easier