leaving a reduced / non tip to a server at a
restaurant for failure to bring you a drink refill (or even ask if you want another).
The
rattlesnake is shaking your ice to try to get their
attention.
When you eat at a
restaurant and your drink runs dry. The server, for whatever reason, will not come by to give you a refill. You summon the "no tip
rattlesnake" by shaking the ice in your glass to try to get their
attention. You either do not get a drink, or it takes forever.