2 is the prime age that dogs come into adulthood. He is letting you know he is the alpha. My guess is that because he is a teacup, he is basically allowed the run of the roost, a common mistake with the cute tiny dogs.
You need to make him understand that you are the boss, not him, and he is the lowest in the pack, not above you. Do not let him do anything, and I mean anything, without having to work for it or without your permission. If he wants to sit on your lap, he needs to do something first like a "sit" before you pick him up. If you give him a treat, make him work for it. Obedience training is always a plus in establishing pack order. If he urinates on you, teach him a down stay and make him down and then stay until YOU release him. A couple of minutes should be sufficient. Make him do a sit stay for his food before YOU release him to eat. Treat him like you would any dog. Since teacups are so tiny, people often have the misconception that they don't need the same type of obedience training a lab or golden would because they are so small they don't get in trouble. Nope.
I would suggest finding a trainer or even going to a class to teach him the basics of obedience. I usually tell people to stay far away from PetSmart type obedience classes, but for him, the basics you can learn are probably good enough. He just needs to know he does not need to mark you because you are not his, he is yours. He is the lowest of the low in the pack. He may be tiny and adorable, but he is still a dog.