“chew the fat” はイギリス英語、”chew the rag” はアメリカ英語で使われる場合が多い。
While Michelle was chewing the fat with Robert, hr got really tired and asked her to shut up.
I sometimes Rashmi late at night and we chewed the fat for one hour or so before going to sleep.
Why don’t you come over Sunday morning and I’ll make some breakfast, we can chew the rag for a couple of hours.
Julia always chew the fat about her funny boy friend, it irritates me.
I had a great time chewing the fat with my old friend Maria.
Our wives have just gone to one of their friend’s party to chew the fat.