Confused 🤷‍♀️

My 4.5 months Exclusively formula fed baby keeps looking for breast & does sucking action on my clothes right on spot .

Sometimes it’s so embarrassing when he does it on my Mom / mil / an aunt who obviously say am denying him his food whereas the truth is I hve an endocrine disorder.

Leaving the bashing aside, is this behaviour normal ? Or some kind of reflex ?