Crios Bhríde, or Brighid’s Cross, is a woven talisman made out of rushes (bents) or broomstraw. In some areas, it was hung on the front door as a blessing. A lot of the Child Ballads have magical references (like Willie's Lady, Child #6, that deals overtly with the many ways in which the jealous mother-in-law's spell must be undone to free Willie's lady). Certainly there's the bedding aspect, but I'm not sure... this is the Cruel Sister after all.