I have avoided the grumpy snake situation by placing the snake, still inside the bag, into the enclosure. I gently open the bag and kinda pull the ends back and let the snake wander out when it feels ready. If the snake is still reluctant in a few hours I might then gently slide the bag/pillowcase out leaving the snake in the enclosure. I have found that after a few hours left alone the snake is moderately less grumpy and removing the bag is much easier. This works better with larger snakes...I'm not so sure it would work so well with something the size of a neonate corn or anything.
Just what I've don ein the past which has worked well for me
Good Luck!