Hi,
The wedged thing is the touching on all sides thing we mentioned earlier when talking about the best type of hides.
Ironically they can also use their waterbowls for the same reason.
What size is he?
Try getting a couple of the terracotts drip trays for putting under flowerpots and chip an entrance hole in one side and put one on each side. The low profile means it feels nice and snug for the snake.
dr del