When your dog knows the release cue and how to sit on cue, put him in a sit, turn and face him, and give him a treat. Pause, and give him another treat for staying in a sit, then release him. Gradually increase the time you wait between treats (it can help to sing the ABC’s in your head and work your way up the alphabet). If your dog gets up before the release cue, that’s ok! It just means he isn’t ready to sit for that long so you can make it easier by going back to a shorter time.
Once your dog can stay in a sit for several seconds, you can begin adding distance. Place him in a sit and say “stay,” take one step back, then step back to the pup, give a treat, and your release word. Continue building in steps, keeping it easy enough that your dog can stay successful. Practice both facing him and walking away with your back turned (which is more realistic).
Submissive urination is a normal way for your puppy to demonstrate submissive behavior. Even a dog that is otherwise housetrained may leave dribbles and puddles of urine at your feet when greeting you. Excitement urination with a puppy is usually caused by lack of bladder control. The puppy is not aware that he is urinating; he's just excited and any punishment will only confuse him.