In 1-quart resealable freezer plastic bag, place chocolate chips and oil; seal bag. Microwave on High 35 to 50 seconds, squeezing chips in bag every 15 seconds, until chips are melted and mixture is smooth. Cut small tip from bottom corner of each bag. Drizzle chocolate over truffles. Refrigerate 30 to 45 minutes or until chocolate is set. Store covered in refrigerator.