Membranes sweep 🤔

So I have never gotten this done before and my dr hasn't mentioned it to me my SIL told me about it and I'm interested in getting it done at my next appointment (39 week appointment) but anyways I have a few questions about it...

Is it really painful?

Do you have to be dilated and thinned out?

What is the requirement to even get it done? my sister told me as long as you are 1-2cm dilated they can do it but Google is saying another thing so anyone that has gotten a membrane sweep give me a little more insight on how it works please 😅