looking to turn my gf... - CuckoldPlace.com

i am a 22 yr old white guy and my gf is 18... we have been together for over a year and plan to be together for awhile. we share plenty, she has been with a few girls i have told her about fantasies about being with guys. im more into cock, love to have it in my mouth to taste a guy cum inside my throat. so when i started seeing black guys i new what was the true breed. me and my gf can be pretty kinky, from handcuffs to name calling ( shes mostly submissive). she has been off on black guys not really being interested but she told me that they are too big and i was good enough, i dont no i a girl that has said a cock was too big. just wondering if anyone had any hints on how to turn her into being a cockslut.
my fantasy is for her to willingly do it on her own, maybe even behind my back a first then powering me to watch. but mostly i want her to think its her idea even though me or the guy is pulling the strings...