Well I would just let it ride and give her time and space.
It's important to voice your support and tell her that this is what you want.
Go shopping with her for new lingerie, pick out a set and mention that this would drive her boyfriend crazy.
Take it from me, or any girl on this site, that once she has experienced superior sex then it's hard if not impossible to give it up.
By the same reason, I hope you realize that there will be no stopping her now.
Not that you should be thinking of stopping her anyway.
Be content that you will be a willing and supportive partner in her discovering her true sexuality.
Black sexxing is like a drug, highly addictive and once a girl is hooked then that's it.
Trust me from someone who knows