GET A WORD IN EDGEWISE (OR EDGEWAYS)

FIND AN OPPORTUNITY TO SAY SOMETHING IN ORDER TO INTERRUPT SOMEONE WHO IS SPEAKING NON STOP.

E.G.

If getting a word in edgewise is a problem for you — just when you want to shout, “Will you ever shut up?” or, “Hey, you idiot. It’s my turn!” consider using some of the following phrases to enter or rejoin a conversation.

http://bigthink.com/influence-power-politics/having-difficulty-getting-a-word-in-edgewise

OR

he can't get a word in edgewise. Last week, when it happened again, she went "bossy" on them.

www.inc.com/sims-wyeth/11-ways-to-get-a-word-in-edgewise.html