Wiktionary
hit the hay
vb. (context idiomatic English) To go to bed.
WordNet
Usage examples of "hit the hay".
After taking a walk about the ship I figure that there ain't no Desperate Desmonds aboard, and having earned my hundred the night before I just curl up in that little cabin and hit the hay.
I was about ready to hit the hay when Detective-Sergeant Green of homicide called me up.