Line baking sheet with wax paper. Set aside. In a medium-sized bowl, mix peanut butter, butter, and sugar with hands to form a smooth stiff dough. Shape into balls using 2 teaspoons of dough for each ball. Place on prepared pan and refrigerate.
Melt shortening or wax and chocolate in the top pot of a double boiler over simmering (not boiling) water. When chocolate mixture is smooth, remove balls from refrigerator. Insert wooden toothpick into each ball and dip into melted chocolate.
Return to wax paper, chocolate side down and remove toothpick. Refrigerate for 30 minutes or more.