Male pup peeing on himself

My 4.5 month old male pup is always peeing on himself! I've only had one other male puppy before and he came to us fixed from the rescue. He never lifted his leg just stretched out his body and went. This guy is not fixed yet. He just stops what he's doing and goes, often peeing on his own legs. The stream is erratic! He is a Boykin Spaniel and is fluffier than any other dog I've had. Can I do anything to help this? Will trimming or shaving off his little penis whiskers help? 😬