How do you toilet poo-train your toddler? She's toilet pee trained but I think poo train is a whole new boss level!

haha.. my friend tried this tip which she read online and it worked for her son. She showed her son the "outcome" (read: contents) of his diaper after he had done the deed. Then she told him that his poo is too much/big for his diaper and he need to "graduate" to the toilet. She proceeded to ask him every now and then (every 5-10mins) when it is near the usual time he does his pooping. Not sure if it will work for your girl though. Can consider.