I've tried it today with a pillow case.
First he didn't want to stay in the pillow. He wanted to slither far away as usual.
I had to point him in the direction of the pillow case a few times.
Then he crawled into it and stayed put for a while.
But I don't know if this is progress since he used the pillow case like his hides. Once he hid in it he got. scared if me again being outside and watching him when he puts his head out. It doesn't seem like he is less scared with it. He is just scared while hiding.
You think it will be better after more times?

Here's a funny pic of our pillow time.
https://www.instagram.com/p/CYg1XMgM...dium=copy_link