This is very common in the NICU and often happens outside the NICU. First find and expert, going to face book and asking for help will give you a slew of options. Too many options to choose from, which is the right option for your baby, which ones do you try first??? I see it all the time, changing out the bottles and the nipples will often make it worse. These tips will help but if you find that you struggling, go to your pediatrician first then find a speech therapist for an evaluation, second.
I always start with the upright and sideling position(full description in my other blog) for paci exercises and then switching to the bottle. It is easier for the baby to handle the milk flow and allows the nipple to be half filled. The cradle hold is harder for these types of babies, as they suck, they get a big mouthful of milk hitting the back of the throat and then tend to choke up.
First try paci exercises before feeds, offer paci and place finger under the chin and one on the cheek. Once the baby starts a rhythmic suck then just add a gentle pressure on the paci so they have to increase their suction. This increases their muscle strength and prepares them for the bottle and brings the tongue forward. If they won't close their mouth, point the paci nipple slightly down towards the tongue. Once they feel the paci on the tongue they usually will close their mouth around it..
After paci exercises, a quick switch to the bottle as they already have the rhythm going. Continue with the finger under the chin and one on the cheek, this will help them keep a good suction on the nipple. Infants that are struggling tend to need a slow flow nipple at first(newborn size) as they are learning/training to feed. As you are feeding and notice the sucking is getting more uncoordinated then go back to the paci exercises to reorganize the sucking. After burping is another time to use the the exercises before going back to the bottle, just a few sucks with the paci this time. If at anytime you notice the baby not pulling milk with sucking or just chewing on the nipple, this means the tongue is too far back, you may need to point the nipple slightly down towards the tongue and use slight tension to draw the tongue back out. If this does not help then go back to paci exercises. Sometime leaning the baby a little more forward will help bring the tongue forward.
Remember this is a learning process for the baby and may take anywhere from a few feeds to a few days to feed effectively. Also know they may get a little tired as they are training, they are now working muscles they have not used before. They are building stamina as well. I always tell my NICU families that "It's the equivalent of giving you a milk shake and making you suck through a coffee straw,,, those are the muscles they are working on".