A mutual acceptance of the end of conversation, agreeing with the outcome to "meetone later", or "get ripped", without requiring the usual spoken acknowledgement of such.
EI (or E.I.) is the acronym for "Extremely Intoxicated." Although this usually applies to those who have consumed alcohol in excess, it can also be applied to any state of intoxication (i.e. drugs, pills, etc.)
Dude, Dan was so EI last night after those Jeggerbombs!