An attempt at Pouring off liquid from a full container is almost always a messy process due to surface tension between the liquid and the container,
the smoother the lip, the greater capability for the liquid to maintain contact with the container and dribble down the side rather than into the desired direction.
You may not want to pour the fluid fast,, as some might suggest. Just attach one of the Pour-Buddy adapters and transfer fluids safely without mess.
If a Perfect Pour adapter is not on hand, this is where field-modification is needed, and results may not be as predictable as would be required.
Don't take a chance with some fluids getting misdirected by surface tension,, inconvenient or costly
Provide an abrupt edge and let the fluids flow!
Another variation of the Pour-buddy, is the Perfect-pour high volume flow adapter for bottles, jugs or milti-gallon containers.
Dispense fluid from a full container without glugging,,,, gasping for air and disrupting fluid flow.
Make that baby pour,,, at a rate that will impress:
"Pouring at high volume, 5gal less than 10sec."