i have the same question. one time i shaved it and it was really itchy. but right now its really long and it gets caught in my zipper and stuff.
Trim it so it's managable.
You wouldn't let the hair on your head keep growing and stay long if it's getting in your way.
Same goes for down below, especially if it's getting caught in zippers or happens to be showing (which may mean it's very long, or you're wearing just pants or unnecessarily short shorts).