Is he neutered? If not he may just be marking. If he is then I don't have any solution for you. Sorry! Good luck with it though!
provide that there are no health issue I can offer a very simple explaination whether it is right or not we'll/ never know because it is not possible to read a dogs mind. but here is a behavioral explaination.He is potty trained. he will cry at the door when he has to go out. Last night for no reason right in front of us, he jumped up on couch, grabbed blanket to nest it under him and just starts peeing on the blanket!!! Why?
The behavior behind this training: Dogs develop substrate preferences for eliminating. By substrate, I mean what they feel under their feet. In their first few weeks of life they need their mother to lick them to stimulate elimination. Around 4 weeks of age they begin to control this themselves. It is a self-rewarding behavior because it feels good. They associate this good feeling with the environment they are in at the time. This is about the same time they are walking well enough to go outside. If they are taken outside enough, several times a day, during this period of development (4 through 8 weeks) they will associate the good feeling of relieving themselves with the grass under their feet, the sky above, and all the smells and sounds of the outdoors. The tactile experience, the texture under the feet, becomes the cue.
If your puppy does not already have this outdoor experience, then you can provide it for him now, to retrain the "substrate preference" he has already learned. Take the pup out about once per hour. This is after play, eating, sleeping, etc. If the puppy can't hold his urine from the crate to the back door while walking, carry him for the first week or so. After a busy play session, take the puppy out, even if it's only been 15 minutes since he last went out. Physical activity produces urine. Inactivity slows the production of urine. This is why a puppy can sleep all night without wetting in the crate, but will urinate on the floor as soon as you let him out of the crate.
So how do you know he needs to go out vs he wants to go out? This type oof mis interpretation can lead to all kinds of problems. So if the dog crys because he wnats to go out. runs around and the activity casue more urine to be produced and he goes. how do you tell the difference?he will cry at the door when he has to go out.