Quarter 1 lime lengthwise, then cut each quarter in half crosswise and divide pieces between 2 (6-ounce) glasses.
Add 1 tablespoon sugar to each glass, then muddle lime pieces by pounding and pressing with a wooden spoon until sugar is dissolved. Fill each glass with ice and add 3 tablespoons (1 1/2 ounces) cachaça to each, stirring well. Make 6 more cocktails in same manner.