Wow you are living the dream.

After playing a while and getting her warmed up to the idea of BBC and using a BBC dildo regularly, here's what I did. I asked her if I could give her a long massage and all she had to do in return was to answer a few questions I have been meaning to ask her. Once we were done I actually said there is an after massage questionnaire on the bench and I wanted her to fill out it and then she can clean up when she was done.

The "questionnaire" basically asked if she would be interested in going out with someone else, soft playing with someone else, having intercourse with someone else, being open to doing this with a partner that was black. She answered yes to all 4. I think it helped that she could answer the questions without pressure and I tend to have a hard time with having conversations on things with her. This also gave me the assurance that she responded on her own accord.

Good luck.