I missed it too, and foound it casually.
You get the first encounter were she is raping a guy.
You can talk (and battle her) or shut up.
If you shut up, the second time you meet her, she will recall your cowardice, and ask if you're turned on or not.
Turned on requires perk Catamite, and you'll get the usual fuck.
Choose not, and she will challenge you, and a fight starts.
Lose the fight (you can use surrender).
After the fight, it's game over, and you get two to choose: die like a man, or live like her woman. (better save before the fight so you can see both)