To "muddle" means to crush ingredients in a glass or cocktail shaker with a muddler or a spoon.
1/2 lime, quartered
1 ablespoon dark brown sugar
2 1/2 ounces tequila
Splash of orange juice
1 stick rock candy
1. With a muddler or wooden spoon, muddle the lime and sugar until the sugar dissolves. Add tequila and orange juice and shake with ice.
2. Strain into a chilled martini glass with ice and garnish with rock candy.
Adapted from Radius