6 months baby starts hitting his head when drinking milk.. is this normal ?

Is he bottle fed or breastfed? Restless hands are normal at this age as they're exploring and like to grab things. Can try giving him sth to hold and see if it stops? My 6.5mo baby sometimes also will find things to hold whenever I breastfeed him like play with my shirt button, scratch me etc and when I feed him via bottle he'll be eager to hold and will twirl his bottle while drinking.