I had one inserted about 6 years ago. I have a poor pain tolerance and my ob did it under a GA at a day procedure centre. DS was 8 weeks old and it was the best 15 minutes sleep I had had in months!! I do know plenty of women who have had them inserted without anaesthetic. I have heard all descriptions from 'mildly uncomfortable' to 'excruciating'! I guess it depends on the individual and the experience of the doctor inserting it.

I did have mine removed in the doctor's surgery. It felt slightly more uncomfortable than a pap smear, but was certainly bearable.