If you are making crushed ice, add regular ice to a Lewis bag and fold up the opening. Smash the ice with a wooden mallet until it gets to the size you like.
Cocktail
Add ice (either crushed or regular ice) to your serving mug.
Add lime juice and tequila to the mug.
Fill the rest of the mug with ginger beer.
If you have a straw or spoon, give the drink a quick stir to mix everything together.
Add the lime slice to the rim of the mug as a garnish, and serve.