Ruth 3:3-4

3Wash thyself therefore, and anoint thee, and put on thy raiment upon thee, and get thee down to the threshing-floor: but make not thyself known to the man, until he shall have done eating and drinking.

4And it shall be, when he lieth down, that thou shalt mark the place where he shall lie, and thou shalt go in, and uncover his feet, and lay thee down; and he will tell thee what thou shalt do.