Do you edit one book at a time or juggle two?

I’ve got two very different manuscripts in progress. I’m already working with an editor on one of them and getting feedback, but I’m wondering if it’s smart (or insane) to start editing the second one too. My logic is: while I’m waiting for feedback on Book A, he could edit Book B, then I swap again. Has anyone done this? Or do you usually focus on polishing one book at a time?