There's a new pixiv meme on the run, uso_desu. Pixiv tags in post #432116 suggest April Fools, but that being pixiv, I'm far from trusting their tags. Does any of our resident pixiv dwellers know the origin of that thing?
For reference, http://www.pixiv.net/tags.php?tag=%E3%81%86%E3%81%9D%E3%81%A7%E3%81%99 seems to be the best tag to browse with.
Updated by jxh2154