How do you know it's a seiyuu_joke and cosplay? I see nothing mentioning Toyosaki Aki on pixiv.

豊崎愛生 as the final tag on the image doesn't mention Toyosaki Aki?

But notice how it doesn't have the * signifying author's tag. And there's absolutely no discussion of it in the comments. The title is "Uiharu Kazari", the comment says "I tried to give her eyes that feel real". The comments are only applauding the good job he did (which is completely true).

Hmm, I learn something new then I guess. I didn't realize it was possible for people other than the author to tag images on Pixiv. Ok, I'll cede then, since that tag was the only thing I was basing it on.