Gosh this is an old thread!
I think if you make your dog do it too much, it can be bad, but just for the bigger dogs.
And ,yes, it is harder to teach a big dog do this, as they have to hold a bigger weight on their hind legs.
It looks so silly to me, that I requested this before, now that ami knows this trick.
![Big Grin :D :D](/members/forums/styles/default/xenforo/smilies/biggrin.png)