This part of the forgoing discussion prompts my thoughts on the subject. None of us have visited Sumatra/Borneo and collected these animals in the wild, that I am aware of...more's the pity.
So we are left to recreate an ideal environment for captives based on what the animal's behavior suggests it might be in nature. Working backwards really.
OK. Here's what have observed and what these observations might mean with respect to behaviors in the wild.
These snakes have short tails. But not because they don't use them. When I put my blood on my lap the very first thing he does is anchor his tail; hooking it securely around my leg, beltloop, etc. When I place him on the lawn, he corkscrews that hook of a tail right into the turf, again like an anchor. In both cases, he then ventures out tenatively, and if alarmed, which happens rather easily, he retracts like a giant molusk.
All that's missing is the "shell" which in nature suggests a burrow. A rat's run through tuff bunchgrass, someting like that.
Also the location of the nostrils on the very top of the nose also suggest the bury themselves in ambush fashion.
In any event, my fellow seems to prefer a concealed situation that is "form-fitting" but allows him to keep his nose, pits and eyeballs exposed ready to detect danger or a feed. More often than not, he will pass up his hides for the substrate.
I have often thought that a suitable piece of pipe would might provide the ideal hide. Extracting could be challenging though...
Hope some of this rambling makes sense..