Vanilla?

I'm reading Mapping the World of Harry Potter. It was the book I pulled off the TBR pile at random this morning.  (Yesterday's book was Phaedra Weldon's Wraith, which had an original premise but didn't hold my attention.)  I finished the essay on the appeal of Snape, and have a question that is based entirely on what I think is an almost throw-away categorization made by the author:  oral sex as kinky, or at the very least not vanilla. 

 . . . Really?

Far be it from me to belittle anyone's preferences -- we've all got our own things, right?  [Doing so would probably invoke some corollary of the Karmic Rule of Kink (tm Dan Savage).]  But is a sex act as common as oral really kinky or non-vanilla?