One IS a drunken fist from the day you are born
from wikipedias taijutsu page
* Name: Suiken, ??, literally "Drunken Fist"
* Type: C-rank, Offensive, Defensive, Short range (0-5m)
* Users: Rock Lee
This unusual style of combat can't be learned or taught. It only occurs naturally, and requires the user to be drunk. Decent skill in some form of combat may also be helpful. Once the former condition is met, the user becomes an unpredictable fighter seemingly unable to discern friend from foe. Lee is particularly talented in this form of combat, hence his sensei's concern whenever he learns that Lee may be exposed to alcohol. The unpredictability combined with Lee's formidable taijutsu skills makes him a force to be reckoned with. Kimimaro Kaguya was only able to hold Lee off by partially activating his cursed seal.
Drunken Fist is based on the 8 Immortals Zui Quan style of Chinese martial arts. In the actual martial art, however, intoxication is not a factor; rather, the 'drunken' movements are used to confuse opponents.