Top off with at least 3 ounces (or to taste) of Topo Chico. Stir.
Garnish with a lime slice.
Notes
* Ratio is two parts tequila to one part freshly squeezed lime juice. * Some bartenders pour out some Topo Chico from a well chilled bottle and add tequila and lime juice directly to the bottle. You'll need to pour out about 3-1/2 ounces of Topo Chico before adding tequila and lime juice to the bottle. Make sure you drink what you pour out so you stay hydrated!