The story I'm looking for was completed. It started with Kagome and her friends facing a demon. Kagome runs and the demon (or demons?) chase her and Sesshomaru saves her. Kagome notices Sesshomaru's red eyes and then they mate (she is willing).
Over the next chapters, Kagome meets Sesshomaru in secret by him 'calling' to her. Each time they meet, they sleep together until eventually Sesshomaru persuades Kagome to be his mate (which she agrees to during one of their tumbles in the forest).
She then gets pregnant and chooses to give up hunting the shards with the group to be by Sesshomaru's side.
I think the story might have started with 'C'...? I could be wrong, but the story itself was complete. I used to have it on my favorite list on ff.net but the author removed it because it had a lot of sex scenes. If anyone knows where I can find the story, please flick me the link
