If after 4–5 attempts the drain remains completely blocked or water begins to seep from under the sink (indicating a leaking trap joint), stop immediately. Continuing can worsen leaks or damage pipes. At this point, the clog is likely solid (e.g., grease, bone, coffee grounds) or located deep in the wall. Next steps include using a sink auger (drain snake) or calling a plumber.
The Art of Plunging a Double Kitchen Sink: A Step-by-Step Guide plunging a double kitchen sink
If your sink has an (the small chrome cylinder next to the faucet for the dishwasher), cover it with a wet rag or tape to prevent water from shooting out. Step 3: Create a Seal and Plunge If after 4–5 attempts the drain remains completely