Show her some interracial porn vids online particularly one with bbc. if she gets wet and such which am sure she would just sort of draw the conversation there like you saying, "can you imagine her doing something like that, that would she enjoy it since she likes big cocks. something along that line i guess and just sort of gauge her reaction and eyes, you know the little things that sort of tells you if she is into it.

New here, but I hope I can help.

Like it was suggested, show her interracial porn .From a woman's point of view, I was introduced to BBC through some really hot ganbang porn vids. Soon the idea of being double penetrated by BBC was all I could think about. I am willing to bet your wife will feel the same.