Boy, this is quite vague...
Sorry!
Again, this is definitely
MA! Please, no kiddies allowed!
From what I can remember, Kagome begged Sesshoumaru to keep her company nightly and he agreed, taking her virginity. At first he was veryyy rough, because that was all he knew? One chapter definitely contained, err, some kind of bestiality and she was on some kind of chest? That only happened once though, iirc. Later on he became more gentle (though still passionate), when he realized she's more than just a lover to him. He did become become wayyy more zealous toward her though.
I do know Kagome got angry at him at some point and tried to break up the agreement, at least once.
Inucast I think is still in the picture. InuYasha and Kagome had some kind of issue in their relationship before ending it? Not sure.
It's
completed, I'm very sure on this.
It's definitely raunchy, but it does have plot.
I thought it might be by Two Hearts, but I didn't see any of that in her works.
Found it at FFnet I think.
Help? Thanks.