in our advanced class we have been working on a technique called "stop" which makes since given that is what the dog is suposed to do. when i say 'stop' she is to stop where ever she is, not sit down just stop. i can't get her to stop away from me. when i say stop and she is directly behind she'll stop but only if i do. if i tell her to stop and she is away from me, she'll just keep walking up to me untill she gets to me then she stops. is there any thing i can do to encourage her to stop?