I think shes cookoo

Ewan and Alicia were having a lovely but slightly heated conversation the other morning. I decided I needed to get a better handle on the conversation, so I stuck my head around the corner whilst in the kitchen. Thats when I saw it. Ewan signing the cookoo signal. You know. Twirling your finger around near your head. As in, I think shes crazy! Well I have absolutely no idea what the conversation was about and once Ewan saw me watching him, he proceeded (ever so slowly) to stop signally with his hand. Where do they get these things from??