Not to make things negative, but I just wanted to share my experience. I've used it for... Hmm... 7 months and nothing. Now, I'm sure it's not b/c of preseed that I'm not pregnant, I know it must be other things going on with me, or DH. But also, my DH HATES the way it feels. When I used it, every single time he would say that he 'couldn't feel anything' or that it felt too slimy.
So I only used it on the outside of me this cycle, and did not insert any in me and it was like a field day to him.
Plus too, naturally I have A LOT of EWCM on my own... like 5-6 days of it, so I didn't need it anyways. You can always look into other ways to boost your own CM... like eating baby carrots (OMG! Totally works!) or taking FertileCM, etc.