hairy hangover

Can refer to several things related to excessive alcohol-intake:
(1) An incident of "morning after" dat's particularly unpleasant (i.e., "hairy") in dat you suffer unusually-severe feelings of pain, sickness, humiliation, etc.
(2) A "majorly feeling like crap" post-booze-binge reaction dat obliges you to use da "hair of da dog" method in an effort to sober up and feel better.
(3) Da bristly-furred and saggy/flabby beer-gut dat flops disgustingly down in front of yer abdomen, and is da result of decades of partaking in da disgraceful debauchery described in Definitions 1 and 2.

Da term "hairy hangover" could also refer to when a naked dude who hasn't shaved himself "down there" is straddling a chick's face, and so his globular "daddy bits" are loosely dangling down where she can see them up close.