You might have better luck on the sand boa forum
I've had sand boas for a month and they have substrate piled on one side and a hide/water dish on the other side. They're usually under the hide, so I just put their mouse right outside of it and they strike from their hides. So, maybe try a hidey-place? Mine are very low so that the top of their backs touch it and they seem to like that.
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My menagerie
3.4 Ball Pythons 1.1 Amazon Tree Boas 1.0 Dumerils Boa 1.1 Kenyan Sand Boas 2.0 Corn Snake 1.2 Black Rat Snakes 1.1.6 Bearded Dragons 1.1.4 Crested Geckos 1.1.4 Eastern Box Turtles 0.3 Chickens 2.1 Cats 1.1 Ferrets plus lots of mice and feeder insects and my Sweety-bird Sydney