Not necessary dear.let him do. Make sure if he/she is not hungry . It will go by it self

<font color ="#3b5998"><b> @616f16498a1b28001309ed20 </b></font> .. don't worry. My son was also doing it.. We use to take his finger out whenever he keeps it. Usually babies do this when they're feeling hungry or sleepy. You give a toy which is clean and safety to be kept in her/his mouth. If it's still continuing, apply any slightly bitter thing like his syrup or fresh neem leaves paste (which you prepare on your own)...but that too in very small amount.

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