Well, here's one with the two of 'em and Inu no Taisho:
A Tangled Mess: The Mating Habits of Kagome Higurashi BY Speedy Tomato (rated MA, of course) .... A
hot story, I tell you.
There is also one in which Inu no Taisho uses Kagome's energy to revive himself back in his tomb. Sessh doesn't want to give up his position and lands so 'Toga' makes a proposal for both of them to mate Kagome. Sessh should mate her first and become the dominant male in the threesome - thus keeping his lands and position. It's somewhere on Dokuga (and I think there are lots of juicy lemons in it)
~lily