When Teddy was about 3-4 months old, I introduced him to the purse. I used leftover Thanksgiving turkey to train him to get in the bag, and now he likes it so much that he gets in all by himself! I leave it on the floor for him to sleep in sometimes. He'll take naps in it when I take him somewhere, too.
Bella is starting to know that when I say, "Let's go Bye-bye" means that she gets to go in her bag. She starts shaking her tail so much that her whole body moves..I love it..She is starting to go in hers too like that.