Gradual feeding gives the grinding chamber time to process material and the drain time to carry it away. A pile that fits into the sink opening may still overwhelm the appliance when pushed in together.
What the observation tells you
Prepare only waste that your particular model permits. Keep packaging and utensils out, start the required water flow, and follow the approved feeding method without putting fingers into the opening. Do not force a mound down with a spoon or improvised tool.
A useful next step
If the sound becomes strained or the unit stops, stop feeding and switch it off. Repeatedly adding water or resetting it is not a remedy for an overloaded chamber.
Manuals and supporting guidance
Model-specific instructions take priority. These references support the practical principles discussed here; they do not diagnose your appliance.