Responses
I think he uses it whenever he's certain that his abilities will not be leaked (like during the bandit arc). He's even more wary now since he's certain that other countries are suspish. Though he wants to raise Luna, he also don't want humanoids to invade Luna Mountain (his territory) but if he's suspected to have left his turf, it's possible for his place to be invaded thus his reluctance to use it.
What i don't get is how can't clevates just use his tentacles while still in human form if don't want to go full wolf, use the shadows to attack, it's not kike it disappears when he's in human form, it'd even be more flexible honestly.