Like Munkeh111 said, it means that you should not throw any meteors at Calaca during the second half of the boss fight.
It is a straight forward fight, but any tips for those that are struggling:
- Try to stay as close to the ground as possible when you are meleeing Calaca; do not go higher than 1 red uppercut. Otherwise you will have too much airtime, and have too little time to prepare to dodge his attacks.
- Listen to him, and pay attention to his animations. When he groans, he's going to do a lava ground attack. His other animations clearly indicate what his next attack is going to be.
Like I said, it is a straightforward fight, so dodge, dodge, dodge. You can easily do this with (mostly) full health at the end.