What is the koriban glitch for exp i dont really know what to do i know it is something with the hissis. help asap.

In the Shyrack caves. Keep clicking on the dead Jedi.

do you mean in the tomb place or just in the regular cave.

It's in the tomb at the back of the Shyrack caves. There will be a dead Jedi in one of the rooms, holding Nebelish's Datapad. Click on him a bunch of times, and Force Storm the bejeezus out of the ensuing Hssiss.

If you are lightside, it behooves you to gain a couple ranks in Drain Force first, or you will find yourself quite short of Force Points.