Has anyone used a head collar/"halti" on their Chi? We just bought one for Finley...our trainer suggested it as the next step in curing his fear aggression issues. He's making progress with the BAT training, but not the way he should/we and she had hoped, so we were discussing additional things to try after his last obedience class. The head collar was just delivered today, so I'm looking for some tips on the best way to get him used to wearing it and "like" it. Thanks!