The fact of the matter where transubstantiation is concerned is that it actually IS cannibalistic in nature since Catholics are expected to believe that the bread and wine are somehow transformed into the body and blood of Jesus. It's impossible to detect any change in either one, but Catholics are supposed to believe that the priest's words bring about this quite magical change. So, you must believe that you're eating Jesus's body and drinking his blood.
What is acceptable to do may have changed since I was a Catholic kid in the 1950's, but I was instructed never to dig at Jesus with a finger when the wafer stuck annoyingly to the roof of my mouth which they often did if your mouth was a bit dry. That was disrespectful , sacrilegious and very much not the thing to do, because back then in any Catholic church where I ever had communion, only the priest could touch the consecrated host. Also, you stuck out your tongue, and the priest laid the wafer on it.
Currently, others than just the priest can touch consecrated wafers and distribute communion, and the wafer is put into the cupped hands of the person taking communion. So, quite a lot is now done differently than when I was a child.
If a consecrated wafer was dropped on the floor back then, one of the altar boys or the priest placed a white cloth over it so that no one would step on the body of Jesus until the priest had time after the Mass had ended to pick up the dropped wafer and dispose of it respectfully and properly. I don't know what would be done today if that happened.