|    
  Hi.  Does she do down at home?  It might be that the floor or ground at training class is cold.  I wouldn't be keen to put my warm belly on the cold floor!  If it's as simple as that try taking a blanket to class for her to do her down on.  Don't let the instructor poo poo this.  You've gotta start somewhere and Pixie is still a wee baby!
 If that's not that then you can try "capturing" the behaviour.  Presumably there are times when she lies down at home.  Keep treats and your clicker in your pocket during this critical "capturing" phase and everytime she lies down naturally say "down" (or whatever word you've decided to use) and click-treat her.  Hopefully she'll quickly associate the command word with the position.  and she should start "offering" the position ie doing a down without being asked when that happens say down and click and treat and PRAISE!
 
 Once she starts offering you can try giving the command when she's not in position and seeing if she'll go into a down.  If she doesn't don't force it and go back to capturing.
 
 You could also try shaping.  Do you have a super tasty treat that Pixie loves - something you don't usually use?  Maybe cheese.  Get her in a sit and without saying anything put the treat on the floor in front of her - when she dips her head to get it click - repeat until she starts offering the head bob. move the treat out a bit so she has go forward and down click treat and repeat.  You should be able to work up to the full down position. Once she starts offering the down position you can start using the command word.  Don't give the word before she's in position otherwise she won't know what particular behaviour the word signifies.  Once she's solid you should be able to give the command and she'll then go into position.
 
 I hope this is helpful and not too long winded.  If you google clicker training you should be able to come up with some tutorials for the basic commands.  Keep it up! training's about the best fun you can have with your dog!
 |