The phrase "putting a howl" implies making a loud and persistent noise. Antonyms for this phrase could be "keeping quiet", "maintaining silence", "remaining silent", or "staying hushed". Other phrases that convey the opposite of "putting a howl" include "whispering", "murmuring", "speaking softly", or "keeping one's voice low". Antonyms for this phrase might also include "calming down", "soothing", "settling", "relaxing", or "pacifying". In any case, there are many words and phrases that convey the opposite of "putting a howl", and they all suggest a more peaceful and subdued state of being.