Abadabab
When two people simultaneously begin speaking, then stop and insist the other begin and then they go back and forth.
Kyle: "So I was..."
Seth: "Didja hear the one..."
Kyle: "Sorry, you first."
Seth: "No you first."
Kyle: "No I insist."
Seth: "Abadabab."
Seth: "Didja hear the one..."
Kyle: "Sorry, you first."
Seth: "No you first."
Kyle: "No I insist."
Seth: "Abadabab."