Wikipedia does not have a page for "sex dice."
...but if it did, it would have an xkcd link right now. I wouldn't be surprised if one surfaced in the next couple days. If it happens, you read it here first.
Every time xkcd updates, its more idiotic fans see fit to alter the Wikipedia article in question to make sure everyone knows that there has been an xkcd comic on the topic. This blog tracks the phenomenon.