One of the ways we tried to get Loki used the baby before he arrived was to play the mobile. When we first played the mobile, Loki was terrified of it and barked lots. So, we just kept playing it and playing it, day after day. Soon enough, he learned that it wasn't a threat to him. He no longer barks at it. I don't think he's quite at the stage of completely ignoring it, but soon enough, I'm sure he'll get there.