Underbite in 4 yrs old..how to break a habit

[AnxietyLevelMax]

My DS is almost 4 and he can perfectly speak, smile, laugh without sticking the bottom jaw out, like an underbite, although he has a habit of very often speaking as he has an underbite or even if he is just playing quietly he sticks his bottom jaw out…i have noticed it recently and started correcting him and reminding but dont see any results…. Any idea how to help him break this habit before it gets worse and start really affecting him?

It could be sensory seeking behavior, he might need some sensory input to help regulate. Reminding him and correcting him isn’t going to achieve anything other than making him feel self conscious

Thanks for your input. what sensory activities should i include for his jaw?
you know when some kids have those moment/phases to act/speak baby’ish…and he is similar. Right now he is playing a game with family and is focused on that and speak perfectly normal.