How to Keep a Dragon in Captivity?

I have always wanted to have a puppy, a fluffy puppy that would lie on my lap and purr, nuzzling my face with its wet nose. This dream could not come true because I traveled to an old castle and was kept captive by a dragon. As the evil dragon's butler, cooking delicious food for him and sorting gold for him, it's boring to death. I was bored, and an idea suddenly came to me, I want to turn this dragon into my puppy. This is almost impossible. This must be very interesting. Concept: Love needs to change for the other person