It just makes them fussy if it falls. To avoid it try not taking the bottle from his mouth so fast and kinda twist it then take it out slowly. that causes it to fall. Just have to be careful with that for around the 1st year or at least until baby can hold his or her head up on their own

Is it harmful? Like what can happen?? @catarina922

My mother in law showed me all a about that. She uses the baby lotion to lift it back up.