The act of pouring vodka into one's eyes instead of the mouth.
This originated as a drinking fad in the U.K. so as to get drunk more quickly than to simply drink the fucking Vodka.
The idea is that the alcohol passes easily through the mucous membrane and enters the bloodstream directly through veins at the back of the eye, although some experts are sceptical about the claims and believe that since those who do it are usually already drunk, they simply convince themselves that it's having such an effect.
However, like the previous section said, it's probably the placebo effect, and a bunch of frat boy idiots think it's uber kawaii to be trendy and edgy by trying out those amazing "British fads" to be more "cultured" while having "fun"
American Frat Boy: "Hay guise let's do some uber kawaii Vodka eyeballing!!!"
Sensible person: "Hey, let's not and say we never fucking thought of this!"