Bad sex?

How is this extract bad sex? I love the mixed metaphors! The imagery... never thought of flaccid dicks as poo poo. Perfect to describe the conception of Adolf Hitler.

Extract From The Castle in the Forest, by Norman Mailer (Little, Brown) pp67-68

Then she was on him. She did not know if this would resuscitate him or end him, but the same spite, sharp as a needle, that had come to her after Fanni's death was in her again. Fanni had told her once what to do. So Klara turned head to foot, and put her most unmentionable part down on his hard-breathing nose and mouth, and took his old battering ram into her lips. Uncle was now as soft as a coil of excrement. She sucked on him nonetheless with an avidity that could come only from the Evil One - that she knew. From there, the impulse had come. So now they both had their heads at the wrong end, and the Evil One was there. He had never been so close before.

The Hound began to come to life. Right in her mouth. It surprised her. Alois had been so limp. But now he was a man again!