I just saw the game being run at GDQ and I’m a little confused as to how one performs the Dino exp glitch on Sargasso. How does that work?

The dino has a weird property where if it is dancing above a death plane, in this case the mud, it'll die repeatedly. We use "cave dino" in particular because it gets lodged between the mud and the rocks, dying infinitely until it's health is depleted by attacks, or the groovitron making it dance runs out.