A farmgirl of 13 takes sex education class and chooses to become a Spinster Slut. The setting is rural modern day on an alternate Earth, with many strange rules and traditions; the same as the other 'Family Lovin' in the Parishes' stories, 'Farmer Frannie the Family Fanny', 'Mama's Patrons', and 'Milkin' and Breedin' at Auntie's Farm'. You should read one or more of those first.