Спільний звук

This prank call went way too far. So this guy decided to prank his girlfriend with a fake coworker calling her, nothing serious, just a joke. At first everything seemed normal, but then it got weird. She started flirting, not joking, actually flirting. The guy listening froze, thinking she was just playing along, but she wasn’t. She said she had a boyfriend, but didn’t sound like she cared at all. Then the caller pushed more and asked if she would ever cheat. There was a pause… and then she said