Buy a bag of spaghnum moss, soak it, wring it out and place it in the hide. You may need to provide a larger hide to accommodate both the moss and your animal.
This creates a humid hide. I keep several species of snake that require high humidity. The ambient in the snake house is about 35 to 40%. I provide humid hides, humid retreats and humid nest boxes and have no issues whatsoever.
+2. Same here.
Ambient humidity in our snake room is also around 35-40% because of the oil heater we use. A little damp sphagnum moss and/or a quick hose down of the substrate with a spray bottle during shed is all ya need.