Cho-geri was only used officially twice in the series. Once as mentioned above, and the other in The Ring of Wind, when Jack is pitted against a pirate sumo wrestler, but misjudged the distance and missed, from lack of practice.
When Jack was first introduced to cho-geri in The Way of the Warrior during his lesson with Sensei Yamada, he was shocked by his teacher's nimbleness and grace, considering his age. But Sensei Yamada proved that mastery of cho-geri has nothing to do with youth.
It is a difficult kick to master and involves launching your entire body off the ground, hands and legs rotating in a way that is not dissimilar to a butterfly in flight, hence its name.