If both ladies are into each other (bi), then that's OK with me. I like doggin' one while she's daty the other, but if neither of you is into the bi stuff, by all means direct all your attention to your client.
I know we all look for something different then the next guy, the problem is knowing what he's looking for, and like you Holly, I wouldn't like wasting my time if both ladies were faking it, (and I think it is usually obvious if that is happening).
My choice is both giving me the attention to reach my goal.