beat one's gums

[beat one's gums] {v. phr.}, {slang} To engage in idle talk, or meaningless chatter; generally to talk too much.

"Stop beating your gums, Jack," Joe cried. "I am falling asleep."

Compare: CHEW THE FAT or CHEW THE RAG, SHOOT THE BREEZE or BAT THE BREEZE or FAN THE BREEZE or SHOOT THE BULL.