A few drops of dish soap added to water will often help soil that has become too dry to accept water, but if you have it out of a large pot and easy to handle you can also just hold it down until it enough air is displaced it no longer floats. Once its wetted again, take it out, you don't want to soak so long as to damage by drowning.

Vermiculite isn't necessarily the best additive for azaleas in containers - it begins as approximately neutral ph when dry but can become more alkaline when exposed to water, the elements. Most garden supply stores, nurseries, box stores will carry a potting medium formulated for best drainage and ph made specifically for azaleas.

And to add to the good advice above, regarding your comment :"have read here that it shouldn't become saturated".

That's a simple and common misinterpretation of how to water a container plant. The entire root ball SHOULD become completely saturated each and every time you water. Water should run all over the place from the drainage holes. However, the soil should be allowed to dry out to an appropriate level in between waterings.

In other words, a plant should be saturated upon watering, but shouldn't STAY saturated.

Little sips of water cause exactly the problem you've described...dry pockets within the root ball in which roots die.