When can I ask to have my membranes swept?

Idk if I even called that the right thing:/FTM. Im 39 weeks today and at my last appointment I was 2 and a half cm dilated. I go back to Dr in the morning and wanted to ask about having this done. Hes already mentioned to me I can schedule an induction at any time (starting today) but Ive repeatedly declined that. I want to labor and deliver as naturally as I can and I know that will be a lot more difficult if I'm induced. But I also dont wanna wind up still being pregnant at 42 weeks and end up having to be induced anyway:( is this something I can ask to have done so that I can go into labor? Ant experiences anyone would like to share?