Unless she misunderstood the question,I don't think you said anything inappropriate there.Give her time to respond,she may be inactive,out of town,busy or preoccupied with some personal business.Or maybe,she never received your email.I would try again.

Just like he said, give it some time and see what happens.

I understand the fustration about not getting email responses, but I have found out sometimes the girls go for the right then and there guys, to make the cash, and then tend to follow up on others.

Hell, if she doesn't write back, then maybe you didn't need that after all.

I don't think you did wrong, but you could have been more specific.  By suggesting a three-way conversation, you are suggesting either MMF or FFM, either of which she, or you, may not be into.

You might ask "is there a friend I might be able to meet you with?"  The worst she can say is "I'd love to see you baby, and to tag team you, but I am not bi."  This is almost verbatum to a response to a request from one of my ATF's.