Perhaps the answer can be found in cyberspace, which is a good place to start to find the truth of this mythical question--
If a female signs her name to the back of the label from a stubby Olympia beer (i.e., an "Oly") . . . and the label has four dots on it . . . does that really mean she's agreed to . . . and has to . . . (well, you know) . . . ?
The myth began (at least among my circle of miscreants) in the 1960s. Somebody heard it from somebody. So, it must have had some merit to it. The process was very very simple--
(1) Have some money.
(2) Get some Olympia beer from somebody (a) old enough to buy it and (b) stupid enough to be willing to break the law by supplying it to incredibly stupid minors with no common sense.
(3) Consume enough Olympia "stubbies" until a label is
found with what appears to be four dots on the back side.
( 5) Have a friend or other impartial observer double-check the marks.
(6) Get a consensus that the label does in fact have the requisite four official dots.
(7) Resist the urge to sell the priceless label for just enough money to buy another case of beer.
(8) Find a pencil.
(9) Find a willing female participant who's gullible enough or sympathetic enough to sign the label.
It's been my observation that nobody has ever gotten past step (5). Never. Ever.