The incompetent drinking process starts the same as the normal drinking process. The stuff leaves the bottle and enters the mouth.
At this point, some of the stuff will exit the mouth again instead of going directly to the stomach. It should be noted that the stuff may pick up some accompanying saliva or other matter in the mouth during its time there, but will otherwise be entirely unchanged, and will not combine wiht anything not already in the mouth. In other words, everything present was bound for eventual swallowing.
Here the stuff re-enters the bottle.
Another drink is taken, and the stuff again enters the mouth.
This time it is successfully swallowed. Once again we must note that nothing has been swallowed that was not originally intended for consumption.
And we again enter the stomach. Digestion ensues.
And it leaves the anus.