I feed all my snakes in smaller rubbermaids. I do not give them lots of room in the feeding enclosure. This makes sure they will eat and not get bored and go hide in another corner, leaving the food.
I leave mine in just long enough to eat and about 5 minutes after they can close there mouth I gently move them back to there cage. Be gentle and use both hands for support.
If they do not eat I usually put the lid on and leave them overnight with the food and it is usually gone in the morning.
No substrate, or just a paper towel.
That is how I do it.
Hope it helps