Help! I'm at my whits end. The bickering is constant. It feels like every interaction is nasty. Yet when they're getting on, they can play well together for hours. My eldest in particular can be so horrible & I can't find any way to punish her that seems to have an effect. She's sent to her room, she has reduced screentime at the weekends, pocket money taken away. I try to model kindness, show her how to behave, but at times with my eldest it feels like I'm living with a stroppy teenager. I guess I'm asking 2 things...how can I get them to be nicer to each other & in particular how can I get my eldest to be kinder & less sassy with us & her sister?