User blog comment:Xilinoc/ch. 544 - Walking With Watchers/@comment-1351982-20130703164138/@comment-5138140-20130703182118

I think it's neither of them. Having seen the ToLOVEru Darkness anime, it seems obvious to me that Kubo named Pero-chan after the onomatopoeia for "lick", which is "peropero". It's the prominent tounge that makes me think so. And I doubt that Kubo has knowlegde regarding American coffee substitues ;-)