I'd just like to add that in addition to agreeing with the above responses, I would skip force feeding and move directly to tube feeding if assist feeding doesn't work. Same results, much less stress. Further, a liquefied meal takes less energy to digest.
Always do the minimally invasive option first, and do so on a minimal basis. A hungry snake will be more apt to eat on it's own. If it doesn't, then assist, and then if a no-go, grab the tube.

If you have no experience with these procedures, I recommend you ask your vet for a demonstration. Learning from the internet can prove hazardous.

Ian