According to Pope Francis on his Meeting with the families in MOA: If you have a problem, a difficulty write a note a place underneath St. Joseph so he can dream about it. In other words: 'pray for this problem'.
Finally I have my own Sleeping St. Joseph, very timely because it's his feast day on the Thursday, March 19. :)
Novena Prayer to St. Joseph
Glorious St.Joseph, faithful follower of Jesus Christ, to you I raise my heart and hands to implore your powerful intercession. Obtain for me from the gentle heart of Jesus all the help and graces necessary for my spiritual and temporal welfare, particularly the grace of a happy death and the favour I now implore.. O guardian of the word incarnate, I feel animated with confidence that your prayers in my behalf will be graciously heard before the throne of God. O glorious St.Joseph, through the love you bear for Jesus Christ and the glory of His name...Amen