This is normal for infants, even older infants. Infants have an "oral fixation". It's actually the first step in learning how to explore. They first taste everything. This is one reason why you'll find infant and toddler toys needing to be larger than a golf ball in all directions, and you'll see toys that say, "not suitable for children 3 years and under" because up to age 3 years kids will generally put things in their mouth to investigate and explore.
Keep your child to his regular feeding schedule. And no, it's not teething. You won't see that until 4 months at the earliest, usually at 6 months teeth will start to pop out.
K. B
mom to 5 including triplets
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