What is Mumbletank?
1.
This is the place in which a person will find themself after they have consumed so much alcohol, chronic or other mind-altering substances that anything and everything that comes out of their mouth will be completely and utterly unintelligible.
That cretin just chugged 2 pints of MD/20-20 and he will be deep in the "mumbletank" for the foreseeable future.
See