. . .You do realize the only instance of that in his books is a woman driven axe-crazy by years of parental neglect and spousal abuse before being handed the keys to a kingdom as big as South America, right? I mean, I'm not going to say there wasn't some contrivance in that subplot, but Cersei is not exactly a posterchild for well-adjusted anything, sexual or no. More than anything, I read it less as fanservice than a sign of her continued ethical disintigration, since her ethos has always been heteronormative.

She's attacking the system, except in a way that's not particularly well-thought out. Which is not exactly out of Cersei's character.