/jp/ - Otaku Culture

I understand the second panel but I'm having trouble with the third one.

I think Yotsuba is telling her father that she ''waved at the onee-chan'' and that her father should do it too. Her father replies with ''father can't seoerate his hands (from the wheel) so Yotsuba should wave for him.''

Why is it ''ふってくれ''?