It could be that he has some UTI or kidney stones, so you should get him checked by vet, just in case. It would be ideal if you could collect some pee, because that helps the vet check for urinary stones. (My own cat often pees in the carrier from excitement, so I don't put any absorbent material in when we go to the vet.)
Cats cannot tell you if they feel pain when urinating. So instead they show you the problem by urinating in very obvious and often inappropriate places.
Especially male cats are very predisposed for urinary stones. If it turns out that he has a problem, you should consider switching to cat food with low grain content or special food to avoid urinary stones.