My snake was off feed for quite a while.. It worried me, until I thought of an extremely easy and simple solution. Here's how you do it.

Get a box that is small, but not too small. It's okay if all four-corners of the box is up against the snake. Snakes feel more secure and satisfied in a smaller, more secluded area.

After you place him in the box, turn out the lights. Turning out the lights will make the snake even more secure, and will stimulate how and when he would eat in the wild.

Lastly, just drop the mouse/rat in and wait for him to eat.

Good luck, and I hope this helps.