Sorry, I was out for the day yesterday.. Weekend trip!! YAY!
This one is a tough one, as I have to admit that I am not the best at it. I have lost animals even after assist feeding for months, just because the animals just aren't responsive.
Start out knowing that assisting feeding means that this little one has special needs. And those with special needs can be just because of a failure to thrive.
Assist feeding is putting the food item down the throat far enough to stimulate the response to swallow. Usually this means the food item up until its shoulders into the throat, if not a bit farther. The animal does have a regurgitation response, and it will attempt to throw it back up if not done correctly, or if the animal is just not interested. This can be tough, and can cause a lot of stress for the animal and yourself. It requires finesse and a bit of tough love. If you can't handle that, DON'T DO IT.
If you have already done the work and gotten the animal to eat, give it plenty of time to adjust to having food. I would say for a baby, a good 5-7 days. It is imperative that you don't over-feed.
If you have successfully managed to get the animal to eat several times ASSIST feeding (not force feeding), after the third time, just put the food item in its mouth (without pushing the item in too far) and see what happens.
If it requires more effort and time, then the animal isn't ready, and you need to give it more time.
If putting food in the mouth works, slowly move towards leaving a prey item in the tub. It will take time, and if it doesn't work, take a step back and just put food in the mouth.
As you can see, this requires an infinite amount of patience.
You can do it!
But again, remember...
SMALL items, every 5-7 days. Don't push it, or you may cause problems.
Good luck, and know I'm rooting for you. This is one of the stressors of being a Ball Python breeder. You can do it!