I had an HSG done in September 2008.

They inject some dye through your tubes and then x-ray to see where the dye goes.
The doctor told me that it would be like a pap smear but it was nothing like that at all. They used much the same instruments to hold my cervix open but that was where the similarities ended.

I found the procedure to be painful and uncomfortable - mine was done without any anaesthetic. So make sure you find out what pain relief they are going to give you. It is the strangest sensation when they inject the dye as it fills up your uterus before it goes through the tubes.

One of my tubes was blocked and while they were there, they fed a little bendy wire through and unblocked it for me there and then. I got pethidine when they did that. I couldn't have had that without pain relief.

Good luck and I hope that was helpful. It might be useful to get information from other forums too as everyone has different experiences with them and this is just mine.

Hugs
S X