When I bottle feed my son with my breastmilk, I feel vibration and the milk going through his tummy. Just wondering if this is normal? Ftm

Tamara • Mommy to my 2 beautiful baby boys, Nathan Louis💙 born August 12, 2017 and Parker Joseph May 6, 2019❤️ My whole world😍

I feel and hear the vibration like down by his tummy.. just making sure this is normal. Sorry if this is a dumb question!