What does it mean to add a boy who has a secret crush and immediately change his head into a dog's head?

Hello, this situation is that he also likes you, which is equivalent to licking the dog himself!

If he doesn't like you, he won't add you, because if he doesn't like someone, he has ten thousand reasons to refuse you!

In particular, he changed his avatar, which is a particularly obvious hint that he wants to be your licking dog!

I just want to be your licking dog.