Theres an entire guide on it in the wiki, but basically you need to start stabbing yourself with the needle aphosdic she drops till you get addicted. plus you need to do a few events with her from the night bar. After that you'll eventually become mate bonded with her(its a perk that decreases aphosadic resistance, although I have a level 90 character so- surpise surpise I was fine with that, mostly because i have a stupid amount of spirit.