The premise of the fic is that Sesshoumaru is courting Kagome in a traditional demonic nature, starting with leaving a demon head next to her while she sleeps. Later Rin starts to help him and so he adds flowers to the display but keeps the demon head in there too. It ends with Kagome speaking to her child having used the story to explain why Sesshoumaru gives her a demon head on their anniversary. I'm pretty sure the fic was a one-shot and that it was located on fanfiction.net.

That would be Tradition by Sunset Miko one of my favorites of all time

You are life saver! Thanks for answering so quickly, and I can definitely agree that it is an awesome fic. Thank you for the help!