You quote the FBI definition, but is that definition actually used in court? I haven’t seen a case that deals with any consent as all consent. It seems, from the article, that the author should have a legal defense as she specifically did not consent to a certain kind of penetration before consenting to any other kind.
As for your reasoning that feminists won’t update the definition of rape… it seems times may be changing because in some of the (very) liberal circles I run in, feminists definitely (now, at least) understand that men can be raped. I think this mentality shift is partly due to the new perception of gender.