[RKDinOKC]

Now she's gonna have to rub his tummy!

Give him the command "belly up" to rub his tummy. My last dog would say rubber tummy then go belly up.
When he starts showing he likes it. Say "Bang" and belly up while pointing your finger like a gun.
The you can call him and as he is running towards you say bang while pointing your finger and he will fall over dead from a full run landing at your feet. Penny my first dog did that except when she played dead she wagged her tail until I told her dead dogs don't wag their tails. She would say laying on her back with her feet up until I said "Be Healed"

It's fun when they learn part of playing is doing the stuff you tell em to.