He knew she was trying to get his mind off of fighting, but being called a kept boy...that made him sound like a whore. He pushed that away. He didn't need to tell his sister that had yet to have sex. She would probably laugh at him.
He was waiting for Izzy to make a move so he was able to move out of the way just at the end so she did not connect, but he did crouch down swiping at her legs.