This dude is unbearable. He's incredibly insecure about his relationship with Kouga, but instead of actually confronting her about it, he goes out with them, makes no effort whatsoever to actually participate in the conversation and just follows them silently wallowing in self-pity, ruining the mood.
When Kouga asked him "What is this weird act supposed to be?", at first I thought she was talking about his previous behavior, not the fact that he was shaking his head like a dog.
Seriously though, why are some people so obsessed with labels?