The act of using the fact that you are, or appear to be drunk to your distinct advantage when trying to achieve personal gain. Usually it is a good idea to greatly overplay your drunk appearance because if you are sober enough to play the tactically drunk card you will appear to be too sober to perform the kinds of ridiculous acts commonly associated with being tactically drunk.
If, in a nightclub's seating area you happen to end up next to someone hot while they are trying to get with someone else you may make yourself appear to be very drunk in order to distract the guy/girl from your rival. These actions can be anything from falling on top of the couple in order to prevent them from hooking up or you could stand up and act as outrageous as possible to focus the attention on you. Works even better with an accomplice--twice the tactical drunkenness is twice as good!
You see a friend in a nightclub falling on top of a couple.
You: Dude what are you doing you've only had two drinks!
Friend: Shhhh! It's alright I'm being tactically drunk...I need to distract these two! Care to help?
You: Sure thing! (You then proceed to dance in a manner that really just can't be ignored while your friend does his own thing.)