Depends what you mean by assist feed. I've seen that used a lot of different ways. Usually after 3 or 4 failed feedings (at week apart minimum) I will do it where you gently tease the head of the prey into their mouth and most of the time they will coil and swallow on their own from there. I try to avoid anything more aggressive than that until I feel like they are getting too close to emaciated that if I go any longer it's going to be really rough on them to recover, at which point I'll use a large pinky mouse or small fuzzy mouse to make it pretty much impossible to spit out so they can still swallow on their own.