Hello and thank you for the questions.
As often occurs, I have a bunch of questions to start.
Does this little one have other sensory issues? Is there an OT who specializes in sensory processing involved? Have you made observations about what this little one is doing with his lips, cheeks and tongue (for purees, and for solids).
I would assume (based on the diagnosis) that you should probably be working on cheek mobility and bilabial closure for spoon, cup etc. If a protrusion/retraction is the primary tongue movement, work on tongue lateralization. Does the child tolerate vibration? If so, use the vibe fine tip for the lateral tongue massage. Try the vibe bite and chew XL head (looks like a yellow chewy tube) if he will not tolerate chewy tubes. You may want to go outside the box and roll the tool from the lateral incisor to the first molar if this child does not like the tool on the molar ridge. By the way, I have just written a book which should be out in June if you need a review of the class (and updated exercises!!!!).