RichThesaurus
foam at the mouth
vs
have one's back up
foam at the mouth
verb
To rage, vent one's anger.
To spew saliva as foam.
have one's back up
verb
To be angry or defensive.
How often have the words
foam at the mouth
and
have one's back up
occurred in a corpus of books?
(source:
Google Ngram Viewer
)