Kurama knows that Shiori can smell Hiei on his sheets. The scent is unmistakable- smoke, cedarwood, sex. It lingers long after the apparition leaves him, weaving itself into his clothing, his bedspread, his hair, his very skin. He wears it as he would expensive perfume.
It reminds him of home.
When the musk fades, notes of sandalwood slowly overwhelmed by rose and earth, it is only then that he allows himself to miss Hiei. But, without fail, a rainy midnight and an inviting open window will fill his lungs with fresh smoke.