1/2 part Tequila
1/2 part 7-Up
With the shot glass you pour half a glass with Tequila and the other half with 7-up. Take the glass already filled with both drinks, take it with palm holding the top of the glass (so the liquid would not come out) and you hit to the table so it will stirr, and you drink the whole.
This is a famous drink in all the beaches in Mexico