Tvad...I'm shocked you do not know the answer to this simple question. Let me help...your average size toilet has an opening big enough for someones head to fit in comfortably (dont ask.) BUTT...and thats a big but...if you can manage to pass all the way through to your neck, then anything you hear beyond that point means that the resolution is at the extremes. ESPECIALLY if you flush at the same time. I have this "friend" who did this you see.
Cheers, and best flushings to you.
Cheers, and best flushings to you.