As far as I can tell, Kat and Coco were never friends, just business associates, if you want to look at it that way. I don't know if Coco got paid to participate, or if she just did it for the thrills (and sex; I can certainly see that being the case). But I do know that their relationship, whatever its nature, did not end well. I don't know why. I'm pretty sure Coco doesn't receive any money whenever Kat sells one of her videos, which certainly sucks. Although maybe that's how Coco is able to maintain a mental block about the whole experience.