bladder control

Question
My 8 month old, male, neutered, yellow lab puppy can go all night and be dry in the morning. He can also go all day 9-10 hours while I'm at work.  He is exercised and let out approximately 5-6 times between 4pm and 9pm, yet sometimes while playing with him in the house he will suddenly drop his toy and pee right in front of me without any indication that he needs to go out.  Other times he will go and ring the bell I have hung on the front door for him to let me know.  He also "sprinkles" when someone comes to the door or if he is having ALOT of fun playing.  Is this physical or behavioral.  I have had him to the vet and she says as far as she can tell he is ok physically.  (no UTI)He gets a treat when he goes outside the right way to enforce good behavior.  CAN you help??

Thanks,  Trudy

Answer
The need to urinate varies with activity.  Urinating while playing is common with younger puppies.  You may have to interrupt him at times and take him out.  also take him out and drain him before you expect anybody.  they do better on an empty bladder.