How feminists "expand the definition" of sexual assault

I hear and read this phrase a lot from pseudo-feminists (people, especially women, who call themselves feminists and use that as an excuse to criticize and disagree with just about everything feminism stands for), anti-feminists (same as pseudo-feminists, but they don't claim to be feminists), men's rights activists (anti-feminists who claim that men, not women, are oppressed), turncoats (they used to identify as feminists, and perhaps still do, and used to pretend to support feminist theory and philosophy, but are now pseudo-feminists, anti-feminists, or men's rights activists). First of all, let's be clear: I am in no way purporting that the continued expansion of the definition of sexual assault couldn't lead us down a dangerous road. If, for example, sexual assault included all anal sex (which, by the way, is a hell of a lot more likely to come from religious Right-wing fanatics than from feminists), or, in a rather mangled quote misattributed to feminist Catharine McKinnon (it was Andrea Dworkin), that all consensual sex between a woman and man is rape (and that wasn't what she meant), there is cause for concern.