How do i teach my nintendog to sit, and come?

okay so i just got this game tonight(the 6th of jan.) and i just got past the part where u teach her to sit and now u have to say lucy like a billion times or so i think, anyway u have to say it to get her to come so u can say sit and it IS NOT WORKING!!! SHE IS A SHETLAND SHEEPDOG, i have a real one and they are very intelligent