Henry Rollins does a lot of
international travel, both on
tours with his
band, and for his own
edification. On one such tour, their
bathroom sink had a little sign over it that said "Be Drinkable".
The correct
interpretation was that the
water that came out of that
tap was
potable, or
safe to drink. They took it in a more
creative way.
In the flavor similar to the annoying "Be Well" signs all over in the movie Demolition Man, they took it to mean "Relax"!
And so, it became sort of an inside joke: "Hey! That guy just hit me!" "Hey, man! Be drinkable!"
...guess you had to have been there...