How does the author use foreshadowing in Slave on the Block?

Hughes arid and sterile portrayal of the Carraways never alludes to sexual passion or physical intimacy between them. It is all relative. The couple has sex when they collaborate artistically, and the only sexual tension between Michael and Anne is in the scene where they first put Luther up on the box and both "simultaneously release" themselves into their respective art forms. This scene foreshadows more sexual tension to erupt further into the story.