well training is twice as hard in some ways. in other ways they help each other. I put one in a crate and work with the other so when i get to the second she has an idea what to do to get a treat and belly rubs. it's funny though they both are good at peeing on the pad but cupcake still has alot of accidents with pooing. cupcake knows her name well however custard hasn't gotten it yet. also they fight alot not rough playing but fighting. and with all the toys they always want the one the other has.