A bicycle as a reward

I am having a hard to time to potty train Aish. There's a lot of method and tips that I have tried until he reached age of 4. Actually, Aish doesn't have any problem to pee at the toilet but he was having a problem to poop. So, my goal was to make him to poop at the toilet before he reach 4 years old.
I found out from his teacher that he didn't poop at school and he only poop whenever he reached home. So, I became desperate. I even promised him to buy a bicycle but he didn't give any cooperation. So, what I did was after I took him from school, I didn't brought him straight home. We went to other places and when he desperate, he didn't have any choice but to go to the toilet. I successfully did it four times and after one week he automatically wants to poop at the toilet.
So today I bought the bicycle for Aish as a reward to him.



Aish with his new red bicycle