So is there some pun involving this one?

Sleeping mask?

Lunatic Red Eyes. It stares to your soul

Here's looking at you, kid.

Sometimes Ao Usagi makes an image that people break their minds to try and find a deeper meaning to it (Gary Larson unwittingly made one with Cow Tools).

Ao Usagi strikes back!

Ao Usagi's Reisen resemble with Melona from queen's blade.

OHMYGO-
I just realized that the ears are tacked to her scalp.

And I don't care about it anymore be knowing the author.

Kumihou said:
Sleeping mask?

A sleeping mask is generally called "eye mask" in Japanese.

Sooner or later, he's gonna level up his bizarre drawing skills too.

henmere said:
A sleeping mask is generally called "eye mask" in Japanese.

pun detected!

You are now aware that her ears are nailed on.

Makareno said:

Not really, its never been explained what those "buttons" are, whether they are pinning fake ears on or just some buttons clipped onto real ears.

Considering there are so many characters with actual animal ears in the series I'd bank on her ears being real, too.