Yule is a birth, and birth is a messy business.
In the old North, women used to give birth in straw. This was called the birthing-litter or the birthing-strew: cushioning, absorbent, and readily disposable.
In fact, straw and strew come from the same verbal root, apparently meaning “to spread.” It was once customary to spread the floors of the house with straw—called halm or haulm, from the same root as Greek kalamos, “reed”—to insulate and absorb spills. Generally the halm had fragrant herbs mingled among it, but even so it must have gotten pretty rank with use. So for many years it was the practice to lay fresh strew for Yule: the Yule-halm. In Sweden this was known as Julglädje, the “Yule-joy.” (The old stuff must have been pretty bad.) Some people would sleep in the Yule-halm so as to leave their beds for the visiting dead who rejoin the family during the holy tide. Straw-dreams were said to be of great omen.