We made the big leap yesterday and for various reasons decided to move Xavier into Mal's room. We were a bit concerned that they would keep each other up, so we put Xav to bed first and once he was asleep, tucked Mal in. They both slept pretty well. Xav woke up a few times between 5:00 and 7:00 though. M or I rushed in there each time, so he wouldn't wake Mal. I needn't have worried. I actually had to wake Mal up at 9:30 this morning!
Tonight didn't go as well. We put them to bed at the same time, like usual. I guess Xav was getting on Mal's nerves. He suddenly shouted out, "stop it! stop it! Yoo-ooo-ou. Shut. Up!" Well, he isn't supposed to say shut up, but it must have worked. All has been quiet ever since.