The taras-chi was allegedly a Jedi debating "tradition" invented by Kyp Durron, though in actuality, it was a gambit created by Durron so that he could express solidarity with Luke Skywalker.
Named after an insect native to Kessel, the technique was spontaneously created by Durron in order to hide his true feelings on the matter of Jacen Solo's ascension toward mastery from Chief of State Cal Omas and Admiral Niathal. Prompted by Niathal to affirm his previously stated position, he told her that she was "unfamiliar with the role of the taras-chi in Jedi debates." He then explained that the taras-chi was a member of a debating body who was appointed to float ideas that run counter to the accepted way of thinking in order to test the validity of ideas. He likened the concept to the court jesters or free press of world governments.
After the meeting was concluded, Mara Jade Skywalker asked just what a 'taras-chi' was and Durron admitted that he borrowed the name of a type of awful tasting insect. Luke thanked him for his support.
Luke Skywalker evidently approved of this idea and began using the new tradition of taras-chi during Council meetings.