Well, first, he probably comes out at night. Second, My Boa did this when she first came here, she picked a spot and stayed there. Oddly enough, it wasnt her hide, she stayed curled up under a tree. What a cutie. As time went by, she explored. When did you get your little guy? I wouldnt push it. Just let him do his thing, he will eventually venture to new places. If you try to force this on him, it'll just stress him out. He'll find new favorite spots, my little girl now has 4 favorite spots. And shes always finding new ones. WHere ever she goes, she stays put for several hours, sometimes all day long. One thing you could try, after handling him, put him on the opposite side of his enclosure, away from his hide. If he crawls right into his hide, let him. But I bet after a while he'll try somewhere else. I did this with my girl, I'd put her on her branch when I was done handling her, she soon discovered her basking spot at the top of her branch, and its now her favorite spot!!! But Boas are more prone to climb then pythons are, so dont be suprised if he doesnt want to be up there too much.
