Foxy knows: sit, down, stand, stay, come, up and down.
I think stand might be a good one. When you say stand he has to stand on all four legs. Trainers say that the best time to use stand is during walking. When your dog responds to stand why don't you tell him to stay while standing. If he can do a sit and down stay a stand stay should not be that hard to teach him.
GOOD LUCK