idiot's advocate 

Someone who actively takes the side of idiocy in a conversation for the sake of having the subject explained, in easier terms, for someone who may not know as much about it. The advocate would typically be up-to-speed with the subject of interest, but ask such questions for someone who might be too embarrassed to do so. See devil's advocate.

Frank, Bob, Carl and I were having a conversation about politics, but Carl doesn't really pay attention to it, so I decided to play the idiot's advocate to catch him up

idiot's advocate by Duv June 22, 2013