what does Edmund tell the others about his and Lucys adventures in Narnia

Lucy and Edmund come bursting out of the wardrobe. Lucy enthusiastically tells Peter and Susan about Narnia and wants Edmund to back up her story. When Lucy tells the story and looks to Edmund for verification, Edmund tells the others that he and Lucy were just playing a game. This gives him an opportunity to act superior to Lucy, but his plan backfires. Instead, Peter and Susan think he has been spitefully playing with Lucy's mind.