A Yellow Tang is where a man, after urinating, but before shaking out the last few drops, then dips his penis into an unsuspecting persons drink, allowing the last few drops of urine to leak out into the drink, creating the Yellow Tang.
Montell - Hey Mike, Scott just went to the pokies
and left his beer
on the table, should we give him a Yellow Tang?
Mike: Fuck oath man, I'm starting to piss now