For his risky work, Peter Telushkin received 5000 rubles, the medal of Santa Anna and the right to receive a free shot of vodka in any tavern in the city. But, he got into the annals of the city's not only for that.
Upon receiving the right for a free shot, signed by Emperor Nicholas I himself, he lost this valuable document pretty quickly. The emperor refused to give him the duplicate and ordered to put the mark on his neck that replaced that document.
So, Telushkin continued to receive his free shots by snapping his fingers at his neck and showing the mark. Since then we use this gesture to indicate in an informal talk that we would like to have a drink or perhaps we have had too much drinks already, although it does not grant us with free shots anymore!