The distaff was the staff which held the flax or wool in spinning. All maidens were engaged in this occupation, and a "spinster" (i.e. one who spins) is still the legal term for an unmarried woman.
St. Blaize (or Blasius) was Bishop of Sebaste in Armenia, and was martyred 316 A.D. His flesh was torn with iron combs, so the wool-staplers have adopted him as their patron saint.
Shrove-tide and Shrove Tuesday derive their names from the ancient practice of confessing one's sins on that day. To be shriven, or shrove, means to obtain absolution from one's sin.