Membrane Sweep?

So I'll be 39 weeks tomorrow (FTM) and last week, my cervix was dilated to 1cm. Today, it was almost to 2cm and I am 80% effaced, plus my baby's head is "REAL low" (CNM's exact words) in my pelvis. She told me she is super impressed with the progress my body has made and that my cervix is the ideal one to have, it's progressing so nicely. BUT, she said if I haven't delivered by my next appointment (a week from today), that she would recommend a membrane sweep to get things going. She described to me what it is and how it works. Has anyone ever had that done, is it painful, and did it work for you? First time mom answers only, please. 😊