My son did this for a short period of time. We would continue to tell him it's not okay to spit the water out. He caught on. Let it run its course and see if it goes away.

Get him one of those Playtex cups with the straw on it. It's a soft silicone and they can stim with that. Andy loved to just lick his. It stopped the spitting of liquids.

My son still does it and he's eight.
seems to feel good to him

Thank you for your input and advice. It is so frustrating to see him do that and then he freaks out about getting sticky. If I say no or stop to him too sternly he panics. He is very sensitive to tone of voice.

Our occupational therapist helps with eating but our speech therapist doesn't