I had one previous to having DD, and I have one now after having DD. The one previous to DD was really uncomfortable. The one after having DD didn't hurt at all! I am guessing it is because my cervix was still stretched out from having her. Did you have a vaginal delivery with DD2?
Re: IUD
I would definitely take some iburofen beforehand. But it wasn't too bad the first time I had it in - I just tried to relax as she was putting it in.
I also recommend the ibuprofen. I took the equivalent of 600mg. I barely felt it at all. I was really nervous before hand, but luckily it was NBD.
Good luck!