most of ours will pee and poo on you at times, but my wife has one trained in a way.
she will pull gizmo out of the pouch and pet him as he sits, after a minute or two he will go pee and poo as she pets him and rubs his top side. Once he is done, she will put him in her bra and he will sleep the day away without going on her 95% of the time.
They CAN'T be trained to go in a "SPOT" like a cat box or a dog kennel we have outside.
Our sophie comes with me to kitchen for 3 or 4 mealworms. After her mealie treats she will poo big time, if you pay attention you can tell, and I can put my arm over trash can and let them fall in.