When Madeleine makes Joseph strip and get under a blanket, it recalls Mrs. Hurd making Jack and Joseph strip and wrap themselves in blankets after Joseph falls through the ice. Together with the implication that Joseph’s mother died when he was young, the parallel between Mrs. Hurd’s behavior and Madeleine’s implies that Joseph falls in love with Madeleine because she offers him affection he hasn’t received from his parents, due to his mother’s death and his father’s abusiveness. In parallel, Madeleine may love Joseph because he shows her attention and affection that she doesn’t receive from her neglectful parents. This confused love, both familial and romantic, leads to them getting “under the red woolen blanket” together, a euphemism for them having sex for the first time.