try to keep the interest sparked, mention it to her casually perhaps during sex while she is about to orgasm, or just did, my advice is to go slow and continue to mention it, perhaps even suggest a FMF perhaps less intimidating for her, and is she is posing to sell her panties, I have the feeling she really in time is ready for the next step, perhaps when she is sending pose posts to sell them you could mention maybe a live view may help your sales, or an open on going views of her totally nude, if she will do that I think as the other guy mentioned she is on the way. When my husband first proposed the idea of wife swapping, I was thinking what is he up to really, but he kept talking to me about it, usually when I was really hot or just orgasmed, and it sounded good. when we finally made it happen, I was hesitant but once we got started, I was all In.